<martin.coffee@round-midnight.org.uk> wrote:
> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> Isn't the engine running all the time?
>>>>
>>>
>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>
>> Sounds like a solution looking for a problem. Why don't they just bin the
>> flywheel and use the engine directly with a small battery and motor for some
>> regen and mild hybrid assistance.
>>
>
> They might do that today but battery technology has moved a long way
> since they were designed and built.
>

You can add super capacitors into the mix now as well as batteries. I
believe some of the Birmingham trams are so fitted.

https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf

Super-capacitors and super-capacitor/battery hybrid trams are a relatively
new addition to catenary-free tram technologies. These trams have evolved
from battery-powered or -assisted trams as an alternative method of energy
storage and capture. Generally, super-capacitor trams have short
operational ranges and charge quickly at stations or points of rest. Most
super-capacitor systems are paired with traction batteries to provide both
high outputs during acceleration and to extend ranges during regular
operation and cruising. Bombardier, Siemens, and CAF are all currently
developing and offering super- capacitor/battery hybrid trams with varying
systems. Chinese light rail manufacturer CSR has also developed a solely
super-capacitor tram at its facilities in Guangzhou with plans to enter
operation before 2020

Super-capacitors have much lower energy capacities compared to batteries
but offer greater charge densities. These densities can be 10 to 100 times
greater than those of batteries and offer significant output during
acceleration or climbing gradients and are achieved through the ‘physical
rather than chemical’ storage of the energy. The structure of
super-capacitors, namely the method by which they store their charge,
allows them to be charged and discharged over 100,000 times - far exceeding
the number of cycles capable by traditional batteries which average 2,000
to 40,000 cycles. Super-capacitors are also able to capture power from
braking sections of track through regenerative breaking, providing further
charging and power generation capacities.
With the exception of the Guangzhou super-capacitor-only tram, all trams
using the technology to date are super-capacitor/battery hybrids. The
batteries help to provide power through maintaining speeds on level
segments of track while the super-capacitors help to provide additional
high-current power during acceleration and climbing gradients. These trams
average top operational speeds of anywhere between 45 to 70 km/h and
average catenary-free operational distances of between 800m and 2.5 km
before recharging. There are a number of super-capacitor-enabled systems
available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
Storage’ (HES) the most popular.

Attractiveness
• Offer greater energy densities and outputs than traction batteries.
• Significantly greater number of life cycles than traction batteries.
• Extremely short recharge times of 10-30 seconds, allowing for near-full
recharges at stations.
• Do not use fossil fuels and improve air quality along lines.
• Do not require expensive third rail technologies such as electrified
ground rails.
• Can be installed on tradition tram carriages and integrated into
propulsion systems.
• Technology supported and in development by many high-end engineering
companies, promising
significant improvements and upgrades in next decade.

Risks
• Currently one of the most expensive tram technologies.
• Very low energy capacities, generally requiring auxiliary or assistant
systems to fully operate
catenary-free.
• High maintenance and replacement costs, although greater life expectancy
than traction batteries.

On 15/04/2022 13:59, Tweed wrote:
> <martin.coffee@round-midnight.org.uk> wrote:
>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Isn't the engine running all the time?
>>>>>
>>>>
>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>
>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>> flywheel and use the engine directly with a small battery and motor for some
>>> regen and mild hybrid assistance.
>>>
>>
>> They might do that today but battery technology has moved a long way
>> since they were designed and built.
>>
>
> You can add super capacitors into the mix now as well as batteries. I
> believe some of the Birmingham trams are so fitted.
>
> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>
> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
> new addition to catenary-free tram technologies. These trams have evolved
> from battery-powered or -assisted trams as an alternative method of energy
> storage and capture. Generally, super-capacitor trams have short
> operational ranges and charge quickly at stations or points of rest. Most
> super-capacitor systems are paired with traction batteries to provide both
> high outputs during acceleration and to extend ranges during regular
> operation and cruising. Bombardier, Siemens, and CAF are all currently
> developing and offering super- capacitor/battery hybrid trams with varying
> systems. Chinese light rail manufacturer CSR has also developed a solely
> super-capacitor tram at its facilities in Guangzhou with plans to enter
> operation before 2020
>
> Super-capacitors have much lower energy capacities compared to batteries
> but offer greater charge densities. These densities can be 10 to 100 times
> greater than those of batteries and offer significant output during
> acceleration or climbing gradients and are achieved through the ‘physical
> rather than chemical’ storage of the energy. The structure of
> super-capacitors, namely the method by which they store their charge,
> allows them to be charged and discharged over 100,000 times - far exceeding
> the number of cycles capable by traditional batteries which average 2,000
> to 40,000 cycles. Super-capacitors are also able to capture power from
> braking sections of track through regenerative breaking, providing further
> charging and power generation capacities.
> With the exception of the Guangzhou super-capacitor-only tram, all trams
> using the technology to date are super-capacitor/battery hybrids. The
> batteries help to provide power through maintaining speeds on level
> segments of track while the super-capacitors help to provide additional
> high-current power during acceleration and climbing gradients. These trams
> average top operational speeds of anywhere between 45 to 70 km/h and
> average catenary-free operational distances of between 800m and 2.5 km
> before recharging. There are a number of super-capacitor-enabled systems
> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
> Storage’ (HES) the most popular.
>
> Attractiveness
> • Offer greater energy densities and outputs than traction batteries.
> • Significantly greater number of life cycles than traction batteries.
> • Extremely short recharge times of 10-30 seconds, allowing for near-full
> recharges at stations.
> • Do not use fossil fuels and improve air quality along lines.
> • Do not require expensive third rail technologies such as electrified
> ground rails.
> • Can be installed on tradition tram carriages and integrated into
> propulsion systems.
> • Technology supported and in development by many high-end engineering
> companies, promising
> significant improvements and upgrades in next decade.
>
> Risks
> • Currently one of the most expensive tram technologies.
> • Very low energy capacities, generally requiring auxiliary or assistant
> systems to fully operate
> catenary-free.
> • High maintenance and replacement costs, although greater life expectancy
> than traction batteries.

"Super-capacitors have much lower energy capacities compared to
batteries but ... greater energy densities". Does that mean that
capacitors with similar capacity to batteries would be smaller and/or
lighter and are not feasible only because of their very high cost?

On 15/04/2022 12:59, Muttley@dastardlyhq.com wrote:
> Would be tricky to have a metro or tram in bristol given the hills. As for
> Bradford, don't know, never been there.

Edinburgh gets around that by running rails (train and tram) east-west
along the flat bits and buses north-south up and down the hills. I
can't recall ever making a local journey by rail here, but the routes
will suit a few people who live and work in the right places.

On 14/04/2022 17:39, hounslow3@yahoo.co.uk wrote:
> I notice that there are a couple of signals and signal signs that are
> not listed in the attachment.
>
> At Dundonald Road, for example, the middle LED in the signal is dark. It
> then lights up before the entire signal clears.
>
> You can see that aspect here:
>
> https://upload.wikimedia.org/wikipedia/commons/0/08/Dundonald_Road_tramstop_look_east.JPG
>
> I don't know if, when the LED lights up, it means CD, put your
> controller into station holding or if it is just means prepare to depart.
>
> Perhaps the signal is an 'Approach Restricted' aspect, however? IIRC,
> there is another signal just like that on the line between stops and
> closer to East Croydon. IIRC, the signal goes through those aspects as a
> tram approaches.
>
> I have also seen the diamond signal sign with the letter 'C'. Does that
> mean coast?

Yes, according to
<https://www.croydon-tramlink.co.uk/info/glossary.shtml#Signs>

On 15/04/2022 09:36, Sam Wilson wrote:
> Charles Ellson <charlesellson@btinternet.com> wrote:
>> On Wed, 13 Apr 2022 22:03:31 -0000 (UTC), Sam Wilson
>> <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>
>>> Charles Ellson <charlesellson@btinternet.com> wrote:
>>>> On Tue, 12 Apr 2022 12:49:05 +0100, Scott
>>>> <newsgroups@gefion.myzen.co.uk> wrote:
>>>>
>>>>> On Tue, 12 Apr 2022 11:30:24 -0000 (UTC), Sam Wilson
>>>>> <ukr@dummy.wislons.fastmail.co.uk> wrote:
>>>>>
>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>> On Tue, 12 Apr 2022 09:23:03 +0100, Scott <newsgroups@gefion.myzen.co.uk> wrote:
>>>>>>>
>>>>>>>> On Mon, 11 Apr 2022 22:08:35 +0100, Charles Ellson
>>>>>>>> <charlesellson@btinternet.com> wrote:
>>>>>>>> [snip]
>>>>>>>>
>>>>>>>> I think OP needs to rephrase the question.
>>>>>>>
>>>>>>> I suppose the distilled question is, "Why are passengers allowed to walk
>>>>>>> across tram tracks, but not light railway
>>>>>>> tracks?".
>>>>>>>
>>>>>>
>>>>>> It?s probably slightly more complex than that. This place has a train:
>>>>>>
>>>>>> <http://www.eastlinks.co.uk/>
>>>>>> <https://goo.gl/maps/hHmicsUZTCL9a2rj6>
>>>>>>
>>>>>> but the track is completely segregated and fenced except for two (or
>>>>>> three?) places, either side of the single station, where footways cross the
>>>>>> track. There is no protection for pedestrians except for the train
>>>>>> announcing its presence, but there are partial fences and no entry signs
>>>>>> for pedestrians at the crossings.
>>>>>>
>>>>>> So this is probably a light railway - it?s certainly not a tram - but
>>>>>> pedestrians are allowed to walk across the tracks at certain, well
>>>>>> specified points, with no gates and no warning other than the train?s
>>>>>> whistle.
>>>>>>
>>>>> Are there any national rail stations where passengers can cross the
>>>>> tracks? I certainly remember this from the past.
>>>>>
>>>> West Highland Line ?
>>>
>>> See the several previous answers to this posting!
>>>
>> I saw yours for Arisaig but I thought there were one or two other
>> stations with island platforms and no footbridge.
>
> I don’t remember any, but my memory is by no means exhaustive. There
> certainly aren’t on the Mallaig extension nor on the section from Perth to
> Inverness. Crianlarich has an island platform with a subway.

I think Corrour may be a pointless answer.
<https://www.nationalrail.co.uk/stations-and-destinations/stations-made-easy/corrour-station-plan>

Certes <none@nowhere.net> wrote:
> On 15/04/2022 13:59, Tweed wrote:
>> <martin.coffee@round-midnight.org.uk> wrote:
>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> Isn't the engine running all the time?
>>>>>>
>>>>>
>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>
>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>> flywheel and use the engine directly with a small battery and motor for some
>>>> regen and mild hybrid assistance.
>>>>
>>>
>>> They might do that today but battery technology has moved a long way
>>> since they were designed and built.
>>>
>>
>> You can add super capacitors into the mix now as well as batteries. I
>> believe some of the Birmingham trams are so fitted.
>>
>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>
>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>> new addition to catenary-free tram technologies. These trams have evolved
>> from battery-powered or -assisted trams as an alternative method of energy
>> storage and capture. Generally, super-capacitor trams have short
>> operational ranges and charge quickly at stations or points of rest. Most
>> super-capacitor systems are paired with traction batteries to provide both
>> high outputs during acceleration and to extend ranges during regular
>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>> developing and offering super- capacitor/battery hybrid trams with varying
>> systems. Chinese light rail manufacturer CSR has also developed a solely
>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>> operation before 2020
>>
>> Super-capacitors have much lower energy capacities compared to batteries
>> but offer greater charge densities. These densities can be 10 to 100 times
>> greater than those of batteries and offer significant output during
>> acceleration or climbing gradients and are achieved through the ‘physical
>> rather than chemical’ storage of the energy. The structure of
>> super-capacitors, namely the method by which they store their charge,
>> allows them to be charged and discharged over 100,000 times - far exceeding
>> the number of cycles capable by traditional batteries which average 2,000
>> to 40,000 cycles. Super-capacitors are also able to capture power from
>> braking sections of track through regenerative breaking, providing further
>> charging and power generation capacities.
>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>> using the technology to date are super-capacitor/battery hybrids. The
>> batteries help to provide power through maintaining speeds on level
>> segments of track while the super-capacitors help to provide additional
>> high-current power during acceleration and climbing gradients. These trams
>> average top operational speeds of anywhere between 45 to 70 km/h and
>> average catenary-free operational distances of between 800m and 2.5 km
>> before recharging. There are a number of super-capacitor-enabled systems
>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>> Storage’ (HES) the most popular.
>>
>> Attractiveness
>> • Offer greater energy densities and outputs than traction batteries.
>> • Significantly greater number of life cycles than traction batteries.
>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>> recharges at stations.
>> • Do not use fossil fuels and improve air quality along lines.
>> • Do not require expensive third rail technologies such as electrified
>> ground rails.
>> • Can be installed on tradition tram carriages and integrated into
>> propulsion systems.
>> • Technology supported and in development by many high-end engineering
>> companies, promising
>> significant improvements and upgrades in next decade.
>>
>> Risks
>> • Currently one of the most expensive tram technologies.
>> • Very low energy capacities, generally requiring auxiliary or assistant
>> systems to fully operate
>> catenary-free.
>> • High maintenance and replacement costs, although greater life expectancy
>> than traction batteries.
>
> "Super-capacitors have much lower energy capacities compared to
> batteries but ... greater energy densities". Does that mean that
> capacitors with similar capacity to batteries would be smaller and/or
> lighter and are not feasible only because of their very high cost?
>

I read that bit several times and it doesn’t make sense. What I think they
might be trying to say is they can have much greater peak discharge and
charge currents. Very useful for rapid charge and assisting batteries for
acceleration.

On 15/04/2022 14:55, Tweed wrote:
> Certes <none@nowhere.net> wrote:
>> On 15/04/2022 13:59, Tweed wrote:
>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>> Isn't the engine running all the time?
>>>>>>>
>>>>>>
>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>
>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>> regen and mild hybrid assistance.
>>>>>
>>>>
>>>> They might do that today but battery technology has moved a long way
>>>> since they were designed and built.
>>>>
>>>
>>> You can add super capacitors into the mix now as well as batteries. I
>>> believe some of the Birmingham trams are so fitted.
>>>
>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>
>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>> new addition to catenary-free tram technologies. These trams have evolved
>>> from battery-powered or -assisted trams as an alternative method of energy
>>> storage and capture. Generally, super-capacitor trams have short
>>> operational ranges and charge quickly at stations or points of rest. Most
>>> super-capacitor systems are paired with traction batteries to provide both
>>> high outputs during acceleration and to extend ranges during regular
>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>> developing and offering super- capacitor/battery hybrid trams with varying
>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>> operation before 2020
>>>
>>> Super-capacitors have much lower energy capacities compared to batteries
>>> but offer greater charge densities. These densities can be 10 to 100 times
>>> greater than those of batteries and offer significant output during
>>> acceleration or climbing gradients and are achieved through the ‘physical
>>> rather than chemical’ storage of the energy. The structure of
>>> super-capacitors, namely the method by which they store their charge,
>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>> the number of cycles capable by traditional batteries which average 2,000
>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>> braking sections of track through regenerative breaking, providing further
>>> charging and power generation capacities.
>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>> using the technology to date are super-capacitor/battery hybrids. The
>>> batteries help to provide power through maintaining speeds on level
>>> segments of track while the super-capacitors help to provide additional
>>> high-current power during acceleration and climbing gradients. These trams
>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>> average catenary-free operational distances of between 800m and 2.5 km
>>> before recharging. There are a number of super-capacitor-enabled systems
>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>> Storage’ (HES) the most popular.
>>>
>>> Attractiveness
>>> • Offer greater energy densities and outputs than traction batteries.
>>> • Significantly greater number of life cycles than traction batteries.
>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>> recharges at stations.
>>> • Do not use fossil fuels and improve air quality along lines.
>>> • Do not require expensive third rail technologies such as electrified
>>> ground rails.
>>> • Can be installed on tradition tram carriages and integrated into
>>> propulsion systems.
>>> • Technology supported and in development by many high-end engineering
>>> companies, promising
>>> significant improvements and upgrades in next decade.
>>>
>>> Risks
>>> • Currently one of the most expensive tram technologies.
>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>> systems to fully operate
>>> catenary-free.
>>> • High maintenance and replacement costs, although greater life expectancy
>>> than traction batteries.
>>
>> "Super-capacitors have much lower energy capacities compared to
>> batteries but ... greater energy densities". Does that mean that
>> capacitors with similar capacity to batteries would be smaller and/or
>> lighter and are not feasible only because of their very high cost?
>>
>
> I read that bit several times and it doesn’t make sense. What I think they
> might be trying to say is they can have much greater peak discharge and
> charge currents. Very useful for rapid charge and assisting batteries for
> acceleration.

What you wrote makes more sense than what they wrote. It sounds like a
perfect ingredient of a hybrid system: charge the capacitor as you stop,
discharge it quickly as you start, use the battery for long-range power.

Certes <none@nowhere.net> wrote:
> On 15/04/2022 14:55, Tweed wrote:
>> Certes <none@nowhere.net> wrote:
>>> On 15/04/2022 13:59, Tweed wrote:
>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>> Isn't the engine running all the time?
>>>>>>>>
>>>>>>>
>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>
>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>> regen and mild hybrid assistance.
>>>>>>
>>>>>
>>>>> They might do that today but battery technology has moved a long way
>>>>> since they were designed and built.
>>>>>
>>>>
>>>> You can add super capacitors into the mix now as well as batteries. I
>>>> believe some of the Birmingham trams are so fitted.
>>>>
>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>
>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>> storage and capture. Generally, super-capacitor trams have short
>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>> super-capacitor systems are paired with traction batteries to provide both
>>>> high outputs during acceleration and to extend ranges during regular
>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>> operation before 2020
>>>>
>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>> greater than those of batteries and offer significant output during
>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>> rather than chemical’ storage of the energy. The structure of
>>>> super-capacitors, namely the method by which they store their charge,
>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>> the number of cycles capable by traditional batteries which average 2,000
>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>> braking sections of track through regenerative breaking, providing further
>>>> charging and power generation capacities.
>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>> batteries help to provide power through maintaining speeds on level
>>>> segments of track while the super-capacitors help to provide additional
>>>> high-current power during acceleration and climbing gradients. These trams
>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>> Storage’ (HES) the most popular.
>>>>
>>>> Attractiveness
>>>> • Offer greater energy densities and outputs than traction batteries.
>>>> • Significantly greater number of life cycles than traction batteries.
>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>> recharges at stations.
>>>> • Do not use fossil fuels and improve air quality along lines.
>>>> • Do not require expensive third rail technologies such as electrified
>>>> ground rails.
>>>> • Can be installed on tradition tram carriages and integrated into
>>>> propulsion systems.
>>>> • Technology supported and in development by many high-end engineering
>>>> companies, promising
>>>> significant improvements and upgrades in next decade.
>>>>
>>>> Risks
>>>> • Currently one of the most expensive tram technologies.
>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>> systems to fully operate
>>>> catenary-free.
>>>> • High maintenance and replacement costs, although greater life expectancy
>>>> than traction batteries.
>>>
>>> "Super-capacitors have much lower energy capacities compared to
>>> batteries but ... greater energy densities". Does that mean that
>>> capacitors with similar capacity to batteries would be smaller and/or
>>> lighter and are not feasible only because of their very high cost?
>>>
>>
>> I read that bit several times and it doesn’t make sense. What I think they
>> might be trying to say is they can have much greater peak discharge and
>> charge currents. Very useful for rapid charge and assisting batteries for
>> acceleration.
>
> What you wrote makes more sense than what they wrote. It sounds like a
> perfect ingredient of a hybrid system: charge the capacitor as you stop,
> discharge it quickly as you start, use the battery for long-range power.
>

Seems the Chinese have dispensed with the battery and just use super
capacitors:

https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/

State-of-the-art battery technology enables electric trams to fully
recharge in just 30 seconds. With a 20 km long route, Huai’an has
introduced the longest running electric tram using supercapacitors in the
world.

Huai’an has implemented one of the first electric trams powered by
supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
area of the city. Supercapacitor technology has a number of advantages over
regular batteries, with a 30 second recharging time and long lifetimes.
This means, that Huai’an’s trams can run all day every day for up to ten
years, recharging at each stop on the line. The trams also use energy
recovery technology to salvage 85% of the energy generated from braking.

With no need for overhead cables to power the trams, infrastructure and
maintenance costs are significantly reduced, and the system is less
vulnerable to adverse weather conditions. The CNY 3.7 billion project
carried 7 million passengers in 2016, with about 30% of journeys replacing
private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
While many cities are using electric trams and buses, this is one of the
first in the world to use supercapacitors for energy storage, and plans are
afoot to expand the service even further.

Certes <none@nowhere.net> wrote:
> On 15/04/2022 14:55, Tweed wrote:
>> Certes <none@nowhere.net> wrote:
>>> On 15/04/2022 13:59, Tweed wrote:
>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>> Isn't the engine running all the time?
>>>>>>>>
>>>>>>>
>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>
>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>> regen and mild hybrid assistance.
>>>>>>
>>>>>
>>>>> They might do that today but battery technology has moved a long way
>>>>> since they were designed and built.
>>>>>
>>>>
>>>> You can add super capacitors into the mix now as well as batteries. I
>>>> believe some of the Birmingham trams are so fitted.
>>>>
>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>
>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>> storage and capture. Generally, super-capacitor trams have short
>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>> super-capacitor systems are paired with traction batteries to provide both
>>>> high outputs during acceleration and to extend ranges during regular
>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>> operation before 2020
>>>>
>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>> greater than those of batteries and offer significant output during
>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>> rather than chemical’ storage of the energy. The structure of
>>>> super-capacitors, namely the method by which they store their charge,
>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>> the number of cycles capable by traditional batteries which average 2,000
>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>> braking sections of track through regenerative breaking, providing further
>>>> charging and power generation capacities.
>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>> batteries help to provide power through maintaining speeds on level
>>>> segments of track while the super-capacitors help to provide additional
>>>> high-current power during acceleration and climbing gradients. These trams
>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>> Storage’ (HES) the most popular.
>>>>
>>>> Attractiveness
>>>> • Offer greater energy densities and outputs than traction batteries.
>>>> • Significantly greater number of life cycles than traction batteries.
>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>> recharges at stations.
>>>> • Do not use fossil fuels and improve air quality along lines.
>>>> • Do not require expensive third rail technologies such as electrified
>>>> ground rails.
>>>> • Can be installed on tradition tram carriages and integrated into
>>>> propulsion systems.
>>>> • Technology supported and in development by many high-end engineering
>>>> companies, promising
>>>> significant improvements and upgrades in next decade.
>>>>
>>>> Risks
>>>> • Currently one of the most expensive tram technologies.
>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>> systems to fully operate
>>>> catenary-free.
>>>> • High maintenance and replacement costs, although greater life expectancy
>>>> than traction batteries.
>>>
>>> "Super-capacitors have much lower energy capacities compared to
>>> batteries but ... greater energy densities". Does that mean that
>>> capacitors with similar capacity to batteries would be smaller and/or
>>> lighter and are not feasible only because of their very high cost?
>>>
>>
>> I read that bit several times and it doesn’t make sense. What I think they
>> might be trying to say is they can have much greater peak discharge and
>> charge currents. Very useful for rapid charge and assisting batteries for
>> acceleration.
>
> What you wrote makes more sense than what they wrote. It sounds like a
> perfect ingredient of a hybrid system: charge the capacitor as you stop,
> discharge it quickly as you start, use the battery for long-range power.
>

Yes, I think that's correct. Capacitors can produce or accept very high
currents almost instantly, but not for long. Think of them as sprinters,
whereas batteries are more like marathon runners. Or, they're like
after-burners in jet engines.

On 15/04/2022 15:13, Tweed wrote:
> Certes <none@nowhere.net> wrote:
>> On 15/04/2022 14:55, Tweed wrote:
>>> Certes <none@nowhere.net> wrote:
>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>
>>>>>>>>
>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>
>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>> regen and mild hybrid assistance.
>>>>>>>
>>>>>>
>>>>>> They might do that today but battery technology has moved a long way
>>>>>> since they were designed and built.
>>>>>>
>>>>>
>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>> believe some of the Birmingham trams are so fitted.
>>>>>
>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>
>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>> high outputs during acceleration and to extend ranges during regular
>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>> operation before 2020
>>>>>
>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>> greater than those of batteries and offer significant output during
>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>> rather than chemical’ storage of the energy. The structure of
>>>>> super-capacitors, namely the method by which they store their charge,
>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>> braking sections of track through regenerative breaking, providing further
>>>>> charging and power generation capacities.
>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>> batteries help to provide power through maintaining speeds on level
>>>>> segments of track while the super-capacitors help to provide additional
>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>> Storage’ (HES) the most popular.
>>>>>
>>>>> Attractiveness
>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>> recharges at stations.
>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>> • Do not require expensive third rail technologies such as electrified
>>>>> ground rails.
>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>> propulsion systems.
>>>>> • Technology supported and in development by many high-end engineering
>>>>> companies, promising
>>>>> significant improvements and upgrades in next decade.
>>>>>
>>>>> Risks
>>>>> • Currently one of the most expensive tram technologies.
>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>> systems to fully operate
>>>>> catenary-free.
>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>> than traction batteries.
>>>>
>>>> "Super-capacitors have much lower energy capacities compared to
>>>> batteries but ... greater energy densities". Does that mean that
>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>> lighter and are not feasible only because of their very high cost?
>>>>
>>>
>>> I read that bit several times and it doesn’t make sense. What I think they
>>> might be trying to say is they can have much greater peak discharge and
>>> charge currents. Very useful for rapid charge and assisting batteries for
>>> acceleration.
>>
>> What you wrote makes more sense than what they wrote. It sounds like a
>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>> discharge it quickly as you start, use the battery for long-range power.
>>
>
> Seems the Chinese have dispensed with the battery and just use super
> capacitors:
>
> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>
> State-of-the-art battery technology enables electric trams to fully
> recharge in just 30 seconds. With a 20 km long route, Huai’an has
> introduced the longest running electric tram using supercapacitors in the
> world.
>
> Huai’an has implemented one of the first electric trams powered by
> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
> area of the city. Supercapacitor technology has a number of advantages over
> regular batteries, with a 30 second recharging time and long lifetimes.
> This means, that Huai’an’s trams can run all day every day for up to ten
> years, recharging at each stop on the line. The trams also use energy
> recovery technology to salvage 85% of the energy generated from braking.
>
> With no need for overhead cables to power the trams, infrastructure and
> maintenance costs are significantly reduced, and the system is less
> vulnerable to adverse weather conditions. The CNY 3.7 billion project
> carried 7 million passengers in 2016, with about 30% of journeys replacing
> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
> While many cities are using electric trams and buses, this is one of the
> first in the world to use supercapacitors for energy storage, and plans are
> afoot to expand the service even further.

A tram with 23 stops in just 20 km, recharging at each, won't need to
store much energy. It's a perfect niche market for supercapacitors and
doesn't need a battery. I was thinking about recharging en route and
the concern about live rails. A short third rail that's only live when
it's concealed beneath a stationary tram could be an ideal solution.

Certes <none@nowhere.net> wrote:
> On 15/04/2022 15:13, Tweed wrote:
>> Certes <none@nowhere.net> wrote:
>>> On 15/04/2022 14:55, Tweed wrote:
>>>> Certes <none@nowhere.net> wrote:
>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>
>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>
>>>>>>>
>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>> since they were designed and built.
>>>>>>>
>>>>>>
>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>
>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>
>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>> operation before 2020
>>>>>>
>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>> greater than those of batteries and offer significant output during
>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>> charging and power generation capacities.
>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>> Storage’ (HES) the most popular.
>>>>>>
>>>>>> Attractiveness
>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>> recharges at stations.
>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>> ground rails.
>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>> propulsion systems.
>>>>>> • Technology supported and in development by many high-end engineering
>>>>>> companies, promising
>>>>>> significant improvements and upgrades in next decade.
>>>>>>
>>>>>> Risks
>>>>>> • Currently one of the most expensive tram technologies.
>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>> systems to fully operate
>>>>>> catenary-free.
>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>> than traction batteries.
>>>>>
>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>> batteries but ... greater energy densities". Does that mean that
>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>> lighter and are not feasible only because of their very high cost?
>>>>>
>>>>
>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>> might be trying to say is they can have much greater peak discharge and
>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>> acceleration.
>>>
>>> What you wrote makes more sense than what they wrote. It sounds like a
>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>> discharge it quickly as you start, use the battery for long-range power.
>>>
>>
>> Seems the Chinese have dispensed with the battery and just use super
>> capacitors:
>>
>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>
>> State-of-the-art battery technology enables electric trams to fully
>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>> introduced the longest running electric tram using supercapacitors in the
>> world.
>>
>> Huai’an has implemented one of the first electric trams powered by
>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>> area of the city. Supercapacitor technology has a number of advantages over
>> regular batteries, with a 30 second recharging time and long lifetimes.
>> This means, that Huai’an’s trams can run all day every day for up to ten
>> years, recharging at each stop on the line. The trams also use energy
>> recovery technology to salvage 85% of the energy generated from braking.
>>
>> With no need for overhead cables to power the trams, infrastructure and
>> maintenance costs are significantly reduced, and the system is less
>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>> While many cities are using electric trams and buses, this is one of the
>> first in the world to use supercapacitors for energy storage, and plans are
>> afoot to expand the service even further.
>
> A tram with 23 stops in just 20 km, recharging at each, won't need to
> store much energy. It's a perfect niche market for supercapacitors and
> doesn't need a battery. I was thinking about recharging en route and
> the concern about live rails. A short third rail that's only live when
> it's concealed beneath a stationary tram could be an ideal solution.
>

Certes <none@nowhere.net> wrote:
> On 15/04/2022 15:13, Tweed wrote:
>> Certes <none@nowhere.net> wrote:
>>> On 15/04/2022 14:55, Tweed wrote:
>>>> Certes <none@nowhere.net> wrote:
>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>
>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>
>>>>>>>
>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>> since they were designed and built.
>>>>>>>
>>>>>>
>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>
>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>
>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>> operation before 2020
>>>>>>
>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>> greater than those of batteries and offer significant output during
>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>> charging and power generation capacities.
>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>> Storage’ (HES) the most popular.
>>>>>>
>>>>>> Attractiveness
>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>> recharges at stations.
>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>> ground rails.
>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>> propulsion systems.
>>>>>> • Technology supported and in development by many high-end engineering
>>>>>> companies, promising
>>>>>> significant improvements and upgrades in next decade.
>>>>>>
>>>>>> Risks
>>>>>> • Currently one of the most expensive tram technologies.
>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>> systems to fully operate
>>>>>> catenary-free.
>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>> than traction batteries.
>>>>>
>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>> batteries but ... greater energy densities". Does that mean that
>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>> lighter and are not feasible only because of their very high cost?
>>>>>
>>>>
>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>> might be trying to say is they can have much greater peak discharge and
>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>> acceleration.
>>>
>>> What you wrote makes more sense than what they wrote. It sounds like a
>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>> discharge it quickly as you start, use the battery for long-range power.
>>>
>>
>> Seems the Chinese have dispensed with the battery and just use super
>> capacitors:
>>
>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>
>> State-of-the-art battery technology enables electric trams to fully
>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>> introduced the longest running electric tram using supercapacitors in the
>> world.
>>
>> Huai’an has implemented one of the first electric trams powered by
>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>> area of the city. Supercapacitor technology has a number of advantages over
>> regular batteries, with a 30 second recharging time and long lifetimes.
>> This means, that Huai’an’s trams can run all day every day for up to ten
>> years, recharging at each stop on the line. The trams also use energy
>> recovery technology to salvage 85% of the energy generated from braking.
>>
>> With no need for overhead cables to power the trams, infrastructure and
>> maintenance costs are significantly reduced, and the system is less
>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>> While many cities are using electric trams and buses, this is one of the
>> first in the world to use supercapacitors for energy storage, and plans are
>> afoot to expand the service even further.
>
> A tram with 23 stops in just 20 km, recharging at each, won't need to
> store much energy. It's a perfect niche market for supercapacitors and
> doesn't need a battery. I was thinking about recharging en route and
> the concern about live rails. A short third rail that's only live when
> it's concealed beneath a stationary tram could be an ideal solution.
>

On 15/04/2022 13:00, Muttley@dastardlyhq.com wrote:
> On Fri, 15 Apr 2022 12:53:53 +0100
> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> On 15/04/2022 12:16, Recliner wrote:
>>>>> https://www.alexander-dennis.com/products/single-deck-buses/
>>>>>
>>>>> Enviro200 13-14 tons GVW
>>>>> Enviro200EV 18.7 tons GVW
>>>>>
>>>>>
>>>>
>>>> GVW is not the same as Kerb weight.
>>>
>>> True, but surely the 5 tonnes higher weight for a bus with otherwise similar
>> specs does mean the battery bus is much
>>> heavier than the diesel bus? The battery buses also need larger wheels and
>> tyres than the diesels, 275/70 R22.5 vs
>>> 245/70R19.5 or 265/70R19.
>>
>> He asked for the kerb weights, that's what he got. If he wanted
>> something different perhaps he should have thought about his question
>> before posing it.
>
> Being a pedant doesn't add any gravitas to your argument.
>

You are the one arguing, I just gave the info you asked for. I don't
care either way.

--
Graeme Wall
This account not read.

On 15/04/2022 13:10, Recliner wrote:
> On Fri, 15 Apr 2022 12:53:53 +0100, Graeme Wall <rail@greywall.demon.co.uk> wrote:
>
>> On 15/04/2022 12:16, Recliner wrote:
>>> On Fri, 15 Apr 2022 12:01:49 +0100, Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>>
>>>> On 15/04/2022 11:33, Muttley@dastardlyhq.com wrote:
>>>>> On Fri, 15 Apr 2022 10:23:08 +0100
>>>>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>>>>> On 15/04/2022 08:55, Muttley@dastardlyhq.com wrote:
>>>>>>> On Thu, 14 Apr 2022 18:37:21 +0100
>>>>>>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>>>>>>> On 14/04/2022 16:22, Muttley@dastardlyhq.com wrote:
>>>>>>>>> On Thu, 14 Apr 2022 11:48:46 +0100
>>>>>>>>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>>>>>>>>> On 14/04/2022 11:19, Muttley@dastardlyhq.com wrote:
>>>>>>>>>>>> The whole point of these new trams is that they're very light. That's
>>>>>> why
>>>>>>>>>>>> they're called Coventry Very Light Rail (CVLR).
>>>>>>>>>>>
>>>>>>>>>>> Get back to us when they've actually built one. "Light" is a relative
>>>>>> term
>>>>>>>>>>> when it comes to rail vehicles. Even the PPM weighs 12 tons and thats
>>>>>> with
>>>>>>>>>>> a flywheel, not heavy batteries.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Flywheels are heavy, that is the point of them.
>>>>>>>>>
>>>>>>>>> https://www.focustransport.org/2016/01/double-deck-parry-people-mover.html
>>>>>>>>>
>>>>>>>>> "A typical PPM flywheel is made from steel laminates, 1m in diameter and
>>>>>>>> 500kg
>>>>>>>>> mass"
>>>>>>>>>
>>>>>>>>> Thats the same as an EV car battery and it only lasts for the half mile or
>>>>>> so
>>>>>>>>
>>>>>>>>> the PPM has to crawl along. The battery for a 10+ ton tram will need to
>>>>>>>>> be somewhat larger especially due to all the stop start that'll occur along
>>>>>>
>>>>>>>>> city streets and the longer route.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Rather like the electric buses that are working all day, every day in a
>>>>>>>> number of towns and cities.
>>>>>>>
>>>>>>> Check out the kerb weight of those buses compared to their diesel
>>>>>> counterparts.
>>>>>>>
>>>>>>
>>>>>> Kerb weight of the battery bus: 13-14.4 tonnes
>>>>>>
>>>>>> Kerb weight of the diesel equivalent: 14.4-18 tonnes
>>>>>
>>>>> God knows where you got that from.
>>>>>
>>>>> https://www.alexander-dennis.com/products/single-deck-buses/
>>>>>
>>>>> Enviro200 13-14 tons GVW
>>>>> Enviro200EV 18.7 tons GVW
>>>>>
>>>>>
>>>>
>>>> GVW is not the same as Kerb weight.
>>>
>>> True, but surely the 5 tonnes higher weight for a bus with otherwise similar specs does mean the battery bus is much
>>> heavier than the diesel bus? The battery buses also need larger wheels and tyres than the diesels, 275/70 R22.5 vs
>>> 245/70R19.5 or 265/70R19.
>>
>> He asked for the kerb weights, that's what he got. If he wanted
>> something different perhaps he should have thought about his question
>> before posing it.
>
> You're getting like Roland. Here's another example for you:
>
> ADL Enviro400EV — unladen weight 13.3 tonnes
> ADL Enviro400 MMC — unladen weight 11 tonnes

As I said I gave the info he asked for, I don't give a toss either way.

--
Graeme Wall
This account not read.

On 15/04/2022 14:31, Certes wrote:
> On 15/04/2022 12:59, Muttley@dastardlyhq.com wrote:
>> Would be tricky to have a metro or tram in bristol given the hills. As
>> for
>> Bradford, don't know, never been there.
>
> Edinburgh gets around that by running rails (train and tram) east-west
> along the flat bits and buses north-south up and down the hills.  I
> can't recall ever making a local journey by rail here, but the routes
> will suit a few people who live and work in the right places.

Trams in Sheffield seem to cope with the hills without problems. Both
Bristol and Edinburgh had tram systems in the past that weren't confined
to the flat bits.

--
Graeme Wall
This account not read.

Recliner <recliner.usenet@gmail.com> wrote:
> Certes <none@nowhere.net> wrote:
>> On 15/04/2022 15:13, Tweed wrote:
>>> Certes <none@nowhere.net> wrote:
>>>> On 15/04/2022 14:55, Tweed wrote:
>>>>> Certes <none@nowhere.net> wrote:
>>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>>
>>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>>
>>>>>>>>
>>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>>> since they were designed and built.
>>>>>>>>
>>>>>>>
>>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>>
>>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>>
>>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>>> operation before 2020
>>>>>>>
>>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>>> greater than those of batteries and offer significant output during
>>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>>> charging and power generation capacities.
>>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>>> Storage’ (HES) the most popular.
>>>>>>>
>>>>>>> Attractiveness
>>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>>> recharges at stations.
>>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>>> ground rails.
>>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>>> propulsion systems.
>>>>>>> • Technology supported and in development by many high-end engineering
>>>>>>> companies, promising
>>>>>>> significant improvements and upgrades in next decade.
>>>>>>>
>>>>>>> Risks
>>>>>>> • Currently one of the most expensive tram technologies.
>>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>>> systems to fully operate
>>>>>>> catenary-free.
>>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>>> than traction batteries.
>>>>>>
>>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>>> batteries but ... greater energy densities". Does that mean that
>>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>>> lighter and are not feasible only because of their very high cost?
>>>>>>
>>>>>
>>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>>> might be trying to say is they can have much greater peak discharge and
>>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>>> acceleration.
>>>>
>>>> What you wrote makes more sense than what they wrote. It sounds like a
>>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>>> discharge it quickly as you start, use the battery for long-range power.
>>>>
>>>
>>> Seems the Chinese have dispensed with the battery and just use super
>>> capacitors:
>>>
>>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>>
>>> State-of-the-art battery technology enables electric trams to fully
>>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>>> introduced the longest running electric tram using supercapacitors in the
>>> world.
>>>
>>> Huai’an has implemented one of the first electric trams powered by
>>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>>> area of the city. Supercapacitor technology has a number of advantages over
>>> regular batteries, with a 30 second recharging time and long lifetimes.
>>> This means, that Huai’an’s trams can run all day every day for up to ten
>>> years, recharging at each stop on the line. The trams also use energy
>>> recovery technology to salvage 85% of the energy generated from braking.
>>>
>>> With no need for overhead cables to power the trams, infrastructure and
>>> maintenance costs are significantly reduced, and the system is less
>>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>>> While many cities are using electric trams and buses, this is one of the
>>> first in the world to use supercapacitors for energy storage, and plans are
>>> afoot to expand the service even further.
>>
>> A tram with 23 stops in just 20 km, recharging at each, won't need to
>> store much energy. It's a perfect niche market for supercapacitors and
>> doesn't need a battery. I was thinking about recharging en route and
>> the concern about live rails. A short third rail that's only live when
>> it's concealed beneath a stationary tram could be an ideal solution.
>>
>
> It could even use induction charging (like a toothbrush or phone). It's
> less efficient, but needs no high voltage connectors.
>
>

On Fri, 15 Apr 2022 01:59:05 +0100, Charles Ellson
<charlesellson@btinternet.com> wrote:

>On Thu, 14 Apr 2022 12:21:37 +0100, Mark Goodge
><usenet@listmail.good-stuff.co.uk> wrote:
>
>>On Wed, 13 Apr 2022 22:02:16 +0100, Charles Ellson
>><charlesellson@btinternet.com> wrote:
>>
>>>Trams are excluded from the general definition of
>>>"mechanically-propelled vehicles" to which road traffic signs apply.
>>
>>Do you have a cite for that? Because the Traffic Signs Regulations and
>>General Directions 2002 explicitly exempts trams from obeying traffic
>>lights and mandatory turn signs, something which would not be necessary
>>if they were not otherwise generally subject to signage.
>>
>I think we had something similar a few years back with trams being
>subject to multiple specific examptions rather than more general ones.
>
>There is also case law that a tram is not a "motor vehicle" or
>"mechanically propelled vehicle" (in the context of road traffic
>legislation) as it cannot travel on a road surface if it leaves the
>rails:-
>https://www.linkedin.com/pulse/tram-motor-vehicle-daniel-rothel

It doesn't need to be a motor vehicle, though. All road users are
subject to road signs, unless given either a general exception in
legislation or a specific exception on the signage itself. That's why,
for example, the "No Entry" signs here...

https://goo.gl/maps/nHLPXrumXt1CK7YP7

....have an exception for trams and cycles, as otherwise it would be
unlawful for trams or cycles to pass them.

There are, of course, some general exceptions for various classes of
road user. Cycles are not subject to speed limits, and therefore exempt
from speed limit signs. Pedestrians are exempt from almost all signs
except "No Pedestrians" signs. But the general principle is that
legislation regulating the roads applies to all road users unless
otherwise stated in legislation.

>The Road Traffic Act 1988 also has multiple but varying optional
>exceptions** (including ss.34-48 wherein traffic signs lie) for trams,
>trolley vehicles and guided vehicles. The 1988 Act is possibly just
>the tip of an iceberg of applicable legislation.
>
>** including -
>" s.193A Tramcars and Trolley Vehicles
>(1) The Secretary of State may by regulations provide that such of the
>provisions mentioned in subsection (2) below as are specified in the
>regulations shall not apply, or shall apply with modifications --"

That clause would not be necessary if trams were already exempt. So its
presence is a clear indicator that, by default, trams are subject to
road legislation.

In practice, of course, trams are primarily regulated by their own,
tram-specific signage which, when present, overrides normal traffic
signs anyway. And that's a deliberate choice, in order to remove any
ambiguity. But on the rare occasions that there is no tram-specific
signage, then normal traffic signs do apply.

Mark

On Fri, 15 Apr 2022 15:24:18 +0100, Certes wrote:
....
> A tram with 23 stops in just 20 km, recharging at each, won't need to
> store much energy. It's a perfect niche market for supercapacitors and
> doesn't need a battery. I was thinking about recharging en route and
> the concern about live rails. A short third rail that's only live when
> it's concealed beneath a stationary tram could be an ideal solution.

Not trams but buses, here in MK from 2014 to 2019-ish we had one 20 km
bus route run fully electric, with overnight charging in depot and top-
ups during the day on inductive pads at each end of the route, IIRC 10 or
15 mins pause, so no live contacts (but I imagine a 120 kW magnetic field
might jiggle a few things if you walked over when it was energised). 150
kWh batteries, possibly >500 kWh used per day per bus (it says).

[About 1 hour for the route one-way, running say 18 hours a day, so 18
inductive charge occasions, say 10 mins each at 120 kW = 360 kW plus a
full charge overnight would just about do it; 15 mins would do it easily.]

Stopped after the trial though, all diesel again now. Trial was supposed
to be "successful", I assume in the sense that the buses kept running.

nib

Tweed <usenet.tweed@gmail.com> wrote:
> Certes <none@nowhere.net> wrote:
>> On 15/04/2022 15:13, Tweed wrote:
>>> Certes <none@nowhere.net> wrote:
>>>> On 15/04/2022 14:55, Tweed wrote:
>>>>> Certes <none@nowhere.net> wrote:
>>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>>
>>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>>
>>>>>>>>
>>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>>> since they were designed and built.
>>>>>>>>
>>>>>>>
>>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>>
>>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>>
>>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>>> operation before 2020
>>>>>>>
>>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>>> greater than those of batteries and offer significant output during
>>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>>> charging and power generation capacities.
>>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>>> Storage’ (HES) the most popular.
>>>>>>>
>>>>>>> Attractiveness
>>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>>> recharges at stations.
>>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>>> ground rails.
>>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>>> propulsion systems.
>>>>>>> • Technology supported and in development by many high-end engineering
>>>>>>> companies, promising
>>>>>>> significant improvements and upgrades in next decade.
>>>>>>>
>>>>>>> Risks
>>>>>>> • Currently one of the most expensive tram technologies.
>>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>>> systems to fully operate
>>>>>>> catenary-free.
>>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>>> than traction batteries.
>>>>>>
>>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>>> batteries but ... greater energy densities". Does that mean that
>>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>>> lighter and are not feasible only because of their very high cost?
>>>>>>
>>>>>
>>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>>> might be trying to say is they can have much greater peak discharge and
>>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>>> acceleration.
>>>>
>>>> What you wrote makes more sense than what they wrote. It sounds like a
>>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>>> discharge it quickly as you start, use the battery for long-range power.
>>>>
>>>
>>> Seems the Chinese have dispensed with the battery and just use super
>>> capacitors:
>>>
>>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>>
>>> State-of-the-art battery technology enables electric trams to fully
>>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>>> introduced the longest running electric tram using supercapacitors in the
>>> world.
>>>
>>> Huai’an has implemented one of the first electric trams powered by
>>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>>> area of the city. Supercapacitor technology has a number of advantages over
>>> regular batteries, with a 30 second recharging time and long lifetimes.
>>> This means, that Huai’an’s trams can run all day every day for up to ten
>>> years, recharging at each stop on the line. The trams also use energy
>>> recovery technology to salvage 85% of the energy generated from braking.
>>>
>>> With no need for overhead cables to power the trams, infrastructure and
>>> maintenance costs are significantly reduced, and the system is less
>>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>>> While many cities are using electric trams and buses, this is one of the
>>> first in the world to use supercapacitors for energy storage, and plans are
>>> afoot to expand the service even further.
>>
>> A tram with 23 stops in just 20 km, recharging at each, won't need to
>> store much energy. It's a perfect niche market for supercapacitors and
>> doesn't need a battery. I was thinking about recharging en route and
>> the concern about live rails. A short third rail that's only live when
>> it's concealed beneath a stationary tram could be an ideal solution.
>>
>
> From what I’ve read, supercapacitors store about a quarter of the energy of
> lithium batteries per kg.
>
>

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 15/04/2022 14:31, Certes wrote:
>> On 15/04/2022 12:59, Muttley@dastardlyhq.com wrote:
>>> Would be tricky to have a metro or tram in bristol given the hills. As
>>> for
>>> Bradford, don't know, never been there.
>>
>> Edinburgh gets around that by running rails (train and tram) east-west
>> along the flat bits and buses north-south up and down the hills.  I
>> can't recall ever making a local journey by rail here, but the routes
>> will suit a few people who live and work in the right places.
>
> Trams in Sheffield seem to cope with the hills without problems. Both
> Bristol and Edinburgh had tram systems in the past that weren't confined
> to the flat bits.
>

Edinburgh initially got around the issue by using cable trams reaching a
route length of 36 miles having previously to attached extra horses to
horse drawn cars. The cable trams got replaced by electric between 1920
and 1924 which allowed through running onto neighbouring systems like Leith
eliminating unpopular changes. Bits of the cable system are still buried,
a pulley remerged during works to extend the present trams to Leith.
<https://www.flickr.com/photos/131232392@N06/51408379101>

GH

<Muttley@dastardlyhq.com> wrote:
> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> Isn't the engine running all the time?
>>>
>>
>> Yes, but it very definitely is used to spin the flywheel up to speed before
>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>
> Sounds like a solution looking for a problem.

Parry has been a solution looking for a problem for around 30 years now.

Even when its niche became mainstream, it was beaten to it by improved
battery and capacitor tech.

> Why don't they just bin the
> flywheel and use the engine directly with a small battery and motor for some
> regen and mild hybrid assistance.
>

When the Parry principle was developed, and even when the Stourbridge
vehicles were introduced, the battery technology wasn't available to
achieve this.

I doubt that Parry will move on from flywheel to battery; the company's
sole reason for existence is to promote John Parry's flywheel propulsion
ideas.

Anna Noyd-Dryver

<Muttley@dastardlyhq.com> wrote:
> On Fri, 15 Apr 2022 10:33:23 -0000 (UTC)
> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>> Marland <gemehabal@btinternet.co.uk> wrote:
>>> Plenty of views of old style trams negotiating floods around the web,
>>> wether damage to motors was worthwhile is another question but old style DC
>>> traction equipment was fairly robust or easy to swap out.
>>> Modern stuff is probably more delicate so its probably not wise but noone
>>> seems to have told this Dublin driver.
>>>
>>> <https://www.bbc.co.uk/news/av/world-europe-36543780>
>>>
>>>
>>
>> Modern motors and electronics are more likely to be fully-sealed units with
>> no opportunities for water ingress.
>
> Would you put that to the test driving your train if you came across a flooded
> section?
>

A bigger problem for trains in the past has been water damage to roller
bearings, rather than electrical equipment.

Clearly what a driver should do in each situation depends on the
instructions given by their employer and the relevant infrastructure
operator.

If I came across previously unreported flooding at linespeed, I wouldn't
have much choice about what happens.

If it's known flooding, I would follow the instructions given by control
and signaller; gWr's instructions are slightly more restrictive than NR's.

Water above railhead, train movements only if authorised by control.

Water between bottom of railhead and top of railhead, 5mph.

Between top of sleepers and bottom of railhead, NR say linespeed, gWr say
20mph (143 150 769) 50mph (158 16x 387 57/Sleeper HST) or linespeed (IET).

Water below the top of the sleepers, linespeed.

None of which is relevant to a tramway running through the streets.

The other consideration for railways rather than street tramways, is that
if the floodwater is flowing and May dislodge ballast, trains can't run.

Anna Noyd-Dryver

Recliner <recliner.usenet@gmail.com> wrote:
> Tweed <usenet.tweed@gmail.com> wrote:
>> Certes <none@nowhere.net> wrote:
>>> On 15/04/2022 15:13, Tweed wrote:
>>>> Certes <none@nowhere.net> wrote:
>>>>> On 15/04/2022 14:55, Tweed wrote:
>>>>>> Certes <none@nowhere.net> wrote:
>>>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>>>
>>>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>>>> since they were designed and built.
>>>>>>>>>
>>>>>>>>
>>>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>>>
>>>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>>>
>>>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>>>> operation before 2020
>>>>>>>>
>>>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>>>> greater than those of batteries and offer significant output during
>>>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>>>> charging and power generation capacities.
>>>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>>>> Storage’ (HES) the most popular.
>>>>>>>>
>>>>>>>> Attractiveness
>>>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>>>> recharges at stations.
>>>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>>>> ground rails.
>>>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>>>> propulsion systems.
>>>>>>>> • Technology supported and in development by many high-end engineering
>>>>>>>> companies, promising
>>>>>>>> significant improvements and upgrades in next decade.
>>>>>>>>
>>>>>>>> Risks
>>>>>>>> • Currently one of the most expensive tram technologies.
>>>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>>>> systems to fully operate
>>>>>>>> catenary-free.
>>>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>>>> than traction batteries.
>>>>>>>
>>>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>>>> batteries but ... greater energy densities". Does that mean that
>>>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>>>> lighter and are not feasible only because of their very high cost?
>>>>>>>
>>>>>>
>>>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>>>> might be trying to say is they can have much greater peak discharge and
>>>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>>>> acceleration.
>>>>>
>>>>> What you wrote makes more sense than what they wrote. It sounds like a
>>>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>>>> discharge it quickly as you start, use the battery for long-range power.
>>>>>
>>>>
>>>> Seems the Chinese have dispensed with the battery and just use super
>>>> capacitors:
>>>>
>>>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>>>
>>>> State-of-the-art battery technology enables electric trams to fully
>>>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>>>> introduced the longest running electric tram using supercapacitors in the
>>>> world.
>>>>
>>>> Huai’an has implemented one of the first electric trams powered by
>>>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>>>> area of the city. Supercapacitor technology has a number of advantages over
>>>> regular batteries, with a 30 second recharging time and long lifetimes.
>>>> This means, that Huai’an’s trams can run all day every day for up to ten
>>>> years, recharging at each stop on the line. The trams also use energy
>>>> recovery technology to salvage 85% of the energy generated from braking.
>>>>
>>>> With no need for overhead cables to power the trams, infrastructure and
>>>> maintenance costs are significantly reduced, and the system is less
>>>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>>>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>>>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>>>> While many cities are using electric trams and buses, this is one of the
>>>> first in the world to use supercapacitors for energy storage, and plans are
>>>> afoot to expand the service even further.
>>>
>>> A tram with 23 stops in just 20 km, recharging at each, won't need to
>>> store much energy. It's a perfect niche market for supercapacitors and
>>> doesn't need a battery. I was thinking about recharging en route and
>>> the concern about live rails. A short third rail that's only live when
>>> it's concealed beneath a stationary tram could be an ideal solution.
>>>
>>
>> From what I’ve read, supercapacitors store about a quarter of the energy of
>> lithium batteries per kg.
>>
>>
>
> It's the other way round. Supercapacitors store around three times as much
> energy per kg as batteries. They're also much more efficient, about 95% vs
> 60-80%. They also recharge very fast without over-heating, and last much
> longer, measured both in cycles and time.
>
> There are two big snags, however: the voltage drops much more as the charge
> falls, and they can be ten times as expensive.
>
>

Tweed <usenet.tweed@gmail.com> wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> Certes <none@nowhere.net> wrote:
>>>> On 15/04/2022 15:13, Tweed wrote:
>>>>> Certes <none@nowhere.net> wrote:
>>>>>> On 15/04/2022 14:55, Tweed wrote:
>>>>>>> Certes <none@nowhere.net> wrote:
>>>>>>>> On 15/04/2022 13:59, Tweed wrote:
>>>>>>>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>>>>>>>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>>>>>>>>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>>>>>>>>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>>> Isn't the engine running all the time?
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>>>>>>>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>>>>>>>>>
>>>>>>>>>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>>>>>>>>>> flywheel and use the engine directly with a small battery and motor for some
>>>>>>>>>>> regen and mild hybrid assistance.
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> They might do that today but battery technology has moved a long way
>>>>>>>>>> since they were designed and built.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> You can add super capacitors into the mix now as well as batteries. I
>>>>>>>>> believe some of the Birmingham trams are so fitted.
>>>>>>>>>
>>>>>>>>> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>>>>>>>>>
>>>>>>>>> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
>>>>>>>>> new addition to catenary-free tram technologies. These trams have evolved
>>>>>>>>> from battery-powered or -assisted trams as an alternative method of energy
>>>>>>>>> storage and capture. Generally, super-capacitor trams have short
>>>>>>>>> operational ranges and charge quickly at stations or points of rest. Most
>>>>>>>>> super-capacitor systems are paired with traction batteries to provide both
>>>>>>>>> high outputs during acceleration and to extend ranges during regular
>>>>>>>>> operation and cruising. Bombardier, Siemens, and CAF are all currently
>>>>>>>>> developing and offering super- capacitor/battery hybrid trams with varying
>>>>>>>>> systems. Chinese light rail manufacturer CSR has also developed a solely
>>>>>>>>> super-capacitor tram at its facilities in Guangzhou with plans to enter
>>>>>>>>> operation before 2020
>>>>>>>>>
>>>>>>>>> Super-capacitors have much lower energy capacities compared to batteries
>>>>>>>>> but offer greater charge densities. These densities can be 10 to 100 times
>>>>>>>>> greater than those of batteries and offer significant output during
>>>>>>>>> acceleration or climbing gradients and are achieved through the ‘physical
>>>>>>>>> rather than chemical’ storage of the energy. The structure of
>>>>>>>>> super-capacitors, namely the method by which they store their charge,
>>>>>>>>> allows them to be charged and discharged over 100,000 times - far exceeding
>>>>>>>>> the number of cycles capable by traditional batteries which average 2,000
>>>>>>>>> to 40,000 cycles. Super-capacitors are also able to capture power from
>>>>>>>>> braking sections of track through regenerative breaking, providing further
>>>>>>>>> charging and power generation capacities.
>>>>>>>>> With the exception of the Guangzhou super-capacitor-only tram, all trams
>>>>>>>>> using the technology to date are super-capacitor/battery hybrids. The
>>>>>>>>> batteries help to provide power through maintaining speeds on level
>>>>>>>>> segments of track while the super-capacitors help to provide additional
>>>>>>>>> high-current power during acceleration and climbing gradients. These trams
>>>>>>>>> average top operational speeds of anywhere between 45 to 70 km/h and
>>>>>>>>> average catenary-free operational distances of between 800m and 2.5 km
>>>>>>>>> before recharging. There are a number of super-capacitor-enabled systems
>>>>>>>>> available on market with CAF’s ‘Rapid Charge Accumulator’ (ACR),
>>>>>>>>> Bombardier’s ‘Mitrac Energy Saver’ (MES), and Siemens’ ‘Hybrid Energy
>>>>>>>>> Storage’ (HES) the most popular.
>>>>>>>>>
>>>>>>>>> Attractiveness
>>>>>>>>> • Offer greater energy densities and outputs than traction batteries.
>>>>>>>>> • Significantly greater number of life cycles than traction batteries.
>>>>>>>>> • Extremely short recharge times of 10-30 seconds, allowing for near-full
>>>>>>>>> recharges at stations.
>>>>>>>>> • Do not use fossil fuels and improve air quality along lines.
>>>>>>>>> • Do not require expensive third rail technologies such as electrified
>>>>>>>>> ground rails.
>>>>>>>>> • Can be installed on tradition tram carriages and integrated into
>>>>>>>>> propulsion systems.
>>>>>>>>> • Technology supported and in development by many high-end engineering
>>>>>>>>> companies, promising
>>>>>>>>> significant improvements and upgrades in next decade.
>>>>>>>>>
>>>>>>>>> Risks
>>>>>>>>> • Currently one of the most expensive tram technologies.
>>>>>>>>> • Very low energy capacities, generally requiring auxiliary or assistant
>>>>>>>>> systems to fully operate
>>>>>>>>> catenary-free.
>>>>>>>>> • High maintenance and replacement costs, although greater life expectancy
>>>>>>>>> than traction batteries.
>>>>>>>>
>>>>>>>> "Super-capacitors have much lower energy capacities compared to
>>>>>>>> batteries but ... greater energy densities". Does that mean that
>>>>>>>> capacitors with similar capacity to batteries would be smaller and/or
>>>>>>>> lighter and are not feasible only because of their very high cost?
>>>>>>>>
>>>>>>>
>>>>>>> I read that bit several times and it doesn’t make sense. What I think they
>>>>>>> might be trying to say is they can have much greater peak discharge and
>>>>>>> charge currents. Very useful for rapid charge and assisting batteries for
>>>>>>> acceleration.
>>>>>>
>>>>>> What you wrote makes more sense than what they wrote. It sounds like a
>>>>>> perfect ingredient of a hybrid system: charge the capacitor as you stop,
>>>>>> discharge it quickly as you start, use the battery for long-range power.
>>>>>>
>>>>>
>>>>> Seems the Chinese have dispensed with the battery and just use super
>>>>> capacitors:
>>>>>
>>>>> https://goexplorer.org/supercapacitor-techno-logy-leading-the-charge-for-public-transport/
>>>>>
>>>>> State-of-the-art battery technology enables electric trams to fully
>>>>> recharge in just 30 seconds. With a 20 km long route, Huai’an has
>>>>> introduced the longest running electric tram using supercapacitors in the
>>>>> world.
>>>>>
>>>>> Huai’an has implemented one of the first electric trams powered by
>>>>> supercapacitors to run on a 20 km route, servicing 23 stops in the busiest
>>>>> area of the city. Supercapacitor technology has a number of advantages over
>>>>> regular batteries, with a 30 second recharging time and long lifetimes.
>>>>> This means, that Huai’an’s trams can run all day every day for up to ten
>>>>> years, recharging at each stop on the line. The trams also use energy
>>>>> recovery technology to salvage 85% of the energy generated from braking.
>>>>>
>>>>> With no need for overhead cables to power the trams, infrastructure and
>>>>> maintenance costs are significantly reduced, and the system is less
>>>>> vulnerable to adverse weather conditions. The CNY 3.7 billion project
>>>>> carried 7 million passengers in 2016, with about 30% of journeys replacing
>>>>> private car trips, avoiding roughly 4,900 tons of CO2 emissions annually.
>>>>> While many cities are using electric trams and buses, this is one of the
>>>>> first in the world to use supercapacitors for energy storage, and plans are
>>>>> afoot to expand the service even further.
>>>>
>>>> A tram with 23 stops in just 20 km, recharging at each, won't need to
>>>> store much energy. It's a perfect niche market for supercapacitors and
>>>> doesn't need a battery. I was thinking about recharging en route and
>>>> the concern about live rails. A short third rail that's only live when
>>>> it's concealed beneath a stationary tram could be an ideal solution.
>>>>
>>>
>>> From what I’ve read, supercapacitors store about a quarter of the energy of
>>> lithium batteries per kg.
>>>
>>>
>>
>> It's the other way round. Supercapacitors store around three times as much
>> energy per kg as batteries. They're also much more efficient, about 95% vs
>> 60-80%. They also recharge very fast without over-heating, and last much
>> longer, measured both in cycles and time.
>>
>> There are two big snags, however: the voltage drops much more as the charge
>> falls, and they can be ten times as expensive.
>>
>>
>
> I disagree
>
> https://en.wikipedia.org/wiki/Supercapacitor
>
> See the table in section 2.6, Wh/kg entry
> Other sources back this up
>
> Not to be confused with Watts/kg, where supercapacitors win, hence the high
> charge and discharge current characteristics. In simple terms a
> supercapacitor has a much lower internal resistance than a battery.

Tweed <usenet.tweed@gmail.com> wrote:
> <martin.coffee@round-midnight.org.uk> wrote:
>> On 15/04/2022 11:35, Muttley@dastardlyhq.com wrote:
>>> On Fri, 15 Apr 2022 10:33:22 -0000 (UTC)
>>> Anna Noyd-Dryver <anna@noyd-dryver.com> wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> Isn't the engine running all the time?
>>>>>
>>>>
>>>> Yes, but it very definitely is used to spin the flywheel up to speed before
>>>> departure. You can hear it, feel it and IIRC see it on the desk gauges.
>>>
>>> Sounds like a solution looking for a problem. Why don't they just bin the
>>> flywheel and use the engine directly with a small battery and motor for some
>>> regen and mild hybrid assistance.
>>>
>>
>> They might do that today but battery technology has moved a long way
>> since they were designed and built.
>>
>
> You can add super capacitors into the mix now as well as batteries. I
> believe some of the Birmingham trams are so fitted.
>
> https://www.polisnetwork.eu/wp-content/uploads/2019/06/hybrid-electric-and-rapid-accumulator-systems-2-finalpolis.pdf
>
> Super-capacitors and super-capacitor/battery hybrid trams are a relatively
> new addition to catenary-free tram technologies. These trams have evolved
> from battery-powered or -assisted trams as an alternative method of energy
> storage and capture. Generally, super-capacitor trams have short
> operational ranges and charge quickly at stations or points of rest. Most
> super-capacitor systems are paired with traction batteries to provide both
> high outputs during acceleration and to extend ranges during regular
> operation and cruising. Bombardier, Siemens, and CAF are all currently
> developing and offering super- capacitor/battery hybrid trams with varying
> systems. Chinese light rail manufacturer CSR has also developed a solely
> super-capacitor tram at its facilities in Guangzhou with plans to enter
> operation before 2020
>

Kaohsiung tramway in Taiwan has operated by supercapacitor only (charged at
every stop) since opening in 2016, with Caf Urbos trams, and now some
Alstom Citadis added to the fleet.

Anna Noyd-Dryver