On Thu, 3 Mar 2022 11:41:35 +0100, Bob <email@domain.com> wrote:

>On 2022-03-03 09:46:38 +0000, Recliner said:
>
>> Bob <email@domain.com> wrote:
>>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>>
>>>> Bob <email@domain.com> wrote:
>>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>>
>>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>>> been done.
>>>>>
>>>>> It would be entirely possible to do this, ultimately all that is needed
>>>>> is a source of heat in the firebox to create hot gases to pass through
>>>>> the boiler tubes and raise steam. A tender could be converted to
>>>>> contain gas bottles, though methane can not easily be stored as a
>>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>>> only a small amount of fuel could be provided. Propane and butane,
>>>>> while gases at ambient temperature and pressure, can be stored as
>>>>> liquids under relatively moderate pressure, as is done for things like
>>>>> caravan or camping fuel for cooking.
>>>>>
>>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>>> the combustion process to occur is quite long compared with light oil
>>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>>> residence time for the combustion process to take place, with things
>>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>>> heat takes place above the brick arch and within the combustion
>>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>>> residence time involved in a gas flame, with a burner under a brick
>>>>> arch on the grate, the combustion will occur lower down, and the
>>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>>> radiant heat in the combustion zone not impinging on water-filled
>>>>> spaces.
>>>>
>>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>>> by water, apart from the grate and the fire hole door. The only way that
>>>> less heat could make its way into the water would be either by heat loss
>>>> through the grate (which could be avoided by using refractory “coals” on
>>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>>> gases leaving the chimney were hotter than normal.
>>>
>>> In a coal firebox, the grate sits under the brick arch, with the
>>> airflow through the grate passing around the back of the brick arch and
>>> into the front part of the firebox/combustion chamber, then into the
>>> fire tubes. The brick arch does not contain water. In a coal fire,
>>> the long residence time means that the actual combustion reaction
>>> oxidising fuel takes a relatively long time, with much of the actual
>>> combustion process happening in the gas path above the brick arch.
>>> Much of the heat release from the combustion will be radiant heat, so
>>> when combustion happens in this region, the radiation will impinge on
>>> the sides and top of the firebox in this area, on metal surfaces
>>> directly backed with water.
>>>
>>> With a gas burner, if the burnier is placed on the grate, the
>>> combustion will be complete before the gas passes around the brick
>>> arch. That means that the radiation from the heat will, to a
>>> significant extent, impinge on the brick arch or grate/ashpan, which do
>>> not have water in them. While this will result in them getting hot and
>>> heat transfer to the gases, the heat transfer from hot gas to the
>>> firebox walls and fire tubes is much less effective than direct radiant
>>> heating of those surfaces. The result will be more heat going up the
>>> chimney.
>>>
>>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>>> output the amount of combustion air needed will be about the same, so the
>>>> volume of flue gas will be the same, and so the flue gas residence time
>>>> will be the same, giving the same opportunity for heat transfer.
>>>
>>> For convective heat transfer (ie from hot gas to surface), yes. But a
>>> signficant part of the heat transfer is from direct radiant heat
>>> transfer, which will be impacted by the fact that the location of the
>>> combustion with a much faster burning fuel, will be in a different
>>> location.
>>>
>>>>> Because a major element in steam locomotive preservation in the UK is
>>>>> authenticity of preserving a historical locomotive, most operators and
>>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>>
>>>> It is becoming increasingly difficult for British steam railways to source
>>>> suitable coal. I know that some railways were trying Russian coal, but
>>>> that door seems to be closing as a result of world events.
>>>
>>> I would expect a conversion to oil burning (diesel or kerosine type
>>> fuel) is far more straightforward in terms of fuel handling and cost,
>>> than gas.
>>>
>>
>> And refuelling is much easier, too.
>>
>> I wonder if smoke could be added in the same way that display aircraft like
>> the Red Arrows do? A smoke generator could be used to produce smoke as and
>> when needed (eg, when pulling away from a station), but kept turned off
>> otherwise. You could even have coloured smoke!
>
>A well-run steam locomotive burning coal should not produce much
>visible smoke. If you see smoke it's because the fireman is not doing
>his job right. Steam exhaust from the blastpipe will be unaffected by
>the fuel source.

It looks a lot better on YouTube if clouds of smoke are pouring out from the loco as it storms up a bank!

Bob <email@domain.com> wrote:
> On 2022-03-03 09:46:38 +0000, Recliner said:
>
>> Bob <email@domain.com> wrote:
>>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>>
>>>> Bob <email@domain.com> wrote:
>>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>>
>>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>>> been done.
>>>>>
>>>>> It would be entirely possible to do this, ultimately all that is needed
>>>>> is a source of heat in the firebox to create hot gases to pass through
>>>>> the boiler tubes and raise steam. A tender could be converted to
>>>>> contain gas bottles, though methane can not easily be stored as a
>>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>>> only a small amount of fuel could be provided. Propane and butane,
>>>>> while gases at ambient temperature and pressure, can be stored as
>>>>> liquids under relatively moderate pressure, as is done for things like
>>>>> caravan or camping fuel for cooking.
>>>>>
>>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>>> the combustion process to occur is quite long compared with light oil
>>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>>> residence time for the combustion process to take place, with things
>>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>>> heat takes place above the brick arch and within the combustion
>>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>>> residence time involved in a gas flame, with a burner under a brick
>>>>> arch on the grate, the combustion will occur lower down, and the
>>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>>> radiant heat in the combustion zone not impinging on water-filled
>>>>> spaces.
>>>>
>>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>>> by water, apart from the grate and the fire hole door. The only way that
>>>> less heat could make its way into the water would be either by heat loss
>>>> through the grate (which could be avoided by using refractory “coals” on
>>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>>> gases leaving the chimney were hotter than normal.
>>>
>>> In a coal firebox, the grate sits under the brick arch, with the
>>> airflow through the grate passing around the back of the brick arch and
>>> into the front part of the firebox/combustion chamber, then into the
>>> fire tubes. The brick arch does not contain water. In a coal fire,
>>> the long residence time means that the actual combustion reaction
>>> oxidising fuel takes a relatively long time, with much of the actual
>>> combustion process happening in the gas path above the brick arch.
>>> Much of the heat release from the combustion will be radiant heat, so
>>> when combustion happens in this region, the radiation will impinge on
>>> the sides and top of the firebox in this area, on metal surfaces
>>> directly backed with water.
>>>
>>> With a gas burner, if the burnier is placed on the grate, the
>>> combustion will be complete before the gas passes around the brick
>>> arch. That means that the radiation from the heat will, to a
>>> significant extent, impinge on the brick arch or grate/ashpan, which do
>>> not have water in them. While this will result in them getting hot and
>>> heat transfer to the gases, the heat transfer from hot gas to the
>>> firebox walls and fire tubes is much less effective than direct radiant
>>> heating of those surfaces. The result will be more heat going up the
>>> chimney.
>>>
>>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>>> output the amount of combustion air needed will be about the same, so the
>>>> volume of flue gas will be the same, and so the flue gas residence time
>>>> will be the same, giving the same opportunity for heat transfer.
>>>
>>> For convective heat transfer (ie from hot gas to surface), yes. But a
>>> signficant part of the heat transfer is from direct radiant heat
>>> transfer, which will be impacted by the fact that the location of the
>>> combustion with a much faster burning fuel, will be in a different
>>> location.
>>>
>>>>> Because a major element in steam locomotive preservation in the UK is
>>>>> authenticity of preserving a historical locomotive, most operators and
>>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>>
>>>> It is becoming increasingly difficult for British steam railways to source
>>>> suitable coal. I know that some railways were trying Russian coal, but
>>>> that door seems to be closing as a result of world events.
>>>
>>> I would expect a conversion to oil burning (diesel or kerosine type
>>> fuel) is far more straightforward in terms of fuel handling and cost,
>>> than gas.
>>>
>>
>> And refuelling is much easier, too.
>>
>> I wonder if smoke could be added in the same way that display aircraft like
>> the Red Arrows do? A smoke generator could be used to produce smoke as and
>> when needed (eg, when pulling away from a station), but kept turned off
>> otherwise. You could even have coloured smoke!
>
> A well-run steam locomotive burning coal should not produce much
> visible smoke. If you see smoke it's because the fireman is not doing
> his job right. Steam exhaust from the blastpipe will be unaffected by
> the fuel source.

You can sometimes see when the fireman has put coal on the fire, because
the exhaust briefly becomes a darker shade of grey.

--
Jeremy Double

On 2022-03-03 10:40:16 +0000, Jeremy Double said:

> Bob <email@domain.com> wrote:
>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>
>>> Bob <email@domain.com> wrote:
>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>
>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>> been done.
>>>>
>>>> It would be entirely possible to do this, ultimately all that is needed
>>>> is a source of heat in the firebox to create hot gases to pass through
>>>> the boiler tubes and raise steam. A tender could be converted to
>>>> contain gas bottles, though methane can not easily be stored as a
>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>> only a small amount of fuel could be provided. Propane and butane,
>>>> while gases at ambient temperature and pressure, can be stored as
>>>> liquids under relatively moderate pressure, as is done for things like
>>>> caravan or camping fuel for cooking.
>>>>
>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>> the combustion process to occur is quite long compared with light oil
>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>> residence time for the combustion process to take place, with things
>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>> heat takes place above the brick arch and within the combustion
>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>> residence time involved in a gas flame, with a burner under a brick
>>>> arch on the grate, the combustion will occur lower down, and the
>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>> radiant heat in the combustion zone not impinging on water-filled
>>>> spaces.
>>>
>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>> by water, apart from the grate and the fire hole door. The only way that
>>> less heat could make its way into the water would be either by heat loss
>>> through the grate (which could be avoided by using refractory “coals” on
>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>> gases leaving the chimney were hotter than normal.
>>
>> In a coal firebox, the grate sits under the brick arch, with the
>> airflow through the grate passing around the back of the brick arch and
>> into the front part of the firebox/combustion chamber, then into the
>> fire tubes. The brick arch does not contain water. In a coal fire,
>> the long residence time means that the actual combustion reaction
>> oxidising fuel takes a relatively long time, with much of the actual
>> combustion process happening in the gas path above the brick arch.
>> Much of the heat release from the combustion will be radiant heat, so
>> when combustion happens in this region, the radiation will impinge on
>> the sides and top of the firebox in this area, on metal surfaces
>> directly backed with water.
>>
>> With a gas burner, if the burnier is placed on the grate, the
>> combustion will be complete before the gas passes around the brick
>> arch. That means that the radiation from the heat will, to a
>> significant extent, impinge on the brick arch or grate/ashpan, which do
>> not have water in them. While this will result in them getting hot and
>> heat transfer to the gases, the heat transfer from hot gas to the
>> firebox walls and fire tubes is much less effective than direct radiant
>> heating of those surfaces. The result will be more heat going up the
>> chimney.
>>
>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>> output the amount of combustion air needed will be about the same, so the
>>> volume of flue gas will be the same, and so the flue gas residence time
>>> will be the same, giving the same opportunity for heat transfer.
>>
>> For convective heat transfer (ie from hot gas to surface), yes. But a
>> signficant part of the heat transfer is from direct radiant heat
>> transfer, which will be impacted by the fact that the location of the
>> combustion with a much faster burning fuel, will be in a different
>> location.
>
> But if the brick arch is hotter, then it will be radiating heat to the
> firebox walls. Also, I worked on some gas fired high temperature process
> furnaces (albeit about 40 years ago) and the flames from the 5 MMBTU/hr
> (about 1.4 MW) burners were long. OK not nearly as big as the pulverised
> coal flame in a power station boiler, but they were certainly long enough
> to make it round the end of a typical locomotive brick arch.
>
> It’s not the fact that it’s a flame that causes radiant heat transfer, it’s
> the temperature of the combustion gases.

Both happen. There is a significant radiant heat release as a direct
result of the chemical reaction of combustion, not just the thermal
radiation from the hot gas itself. The blue colour you see in a
(methane) gas flame is the characteristic emission colour of the
reaction of carbon with oxygen, and is a feature of the flame itself,
not just the fact that the gases are at a high temperature. That
radiation release only occurs where the flame itself is present (and
heat is released in this way outside fo the visible specturm too).

Robin

In message <svq60v$6ef$1@dont-email.me>, at 11:41:35 on Thu, 3 Mar 2022,
Bob <email@domain.com> remarked:

>A well-run steam locomotive burning coal should not produce much
>visible smoke. If you see smoke it's because the fireman is not doing
>his job right. Steam exhaust from the blastpipe will be unaffected by
>the fuel source.

Quite a bit of smoke, and *lots* of steam!

https://youtu.be/9qyZnYyqoKI

[Apologies for video quality, it's getting on for ten years old]
--
Roland Perry

Roland Perry <roland@perry.co.uk> wrote:
> In message <svq60v$6ef$1@dont-email.me>, at 11:41:35 on Thu, 3 Mar 2022,
> Bob <email@domain.com> remarked:
>
>> A well-run steam locomotive burning coal should not produce much
>> visible smoke. If you see smoke it's because the fireman is not doing
>> his job right. Steam exhaust from the blastpipe will be unaffected by
>> the fuel source.
>
> Quite a bit of smoke, and *lots* of steam!
>
> https://youtu.be/9qyZnYyqoKI
>
> [Apologies for video quality, it's getting on for ten years old]

It's funny, I was going to post that Tangmere always seems very smokey. It
can't be because of an individual fireman, so it must be something about
the loco itself.

On Thu, 3 Mar 2022 15:23:34 +0100
Bob <email@domain.com> wrote:
>On 2022-03-03 10:40:16 +0000, Jeremy Double said:
>not just the fact that the gases are at a high temperature. That
>radiation release only occurs where the flame itself is present (and
>heat is released in this way outside fo the visible specturm too).

Given the heat would be infra red thats rather a given.

On 03/03/2022 09:30, Bob wrote:
> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>
>> Bob <email@domain.com> wrote:
>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>
>>>> I’ve just been reading an article about the difficulties of
>>>> obtaining coal
>>>> with low volatile content. The obtainable stuff seems to produce more
>>>> smoke. I’ve read about converting steam locos to oil burning, but
>>>> this led
>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>> bottle in the tender and a suitable burner in the grate? The
>>>> advantages are
>>>> low local pollution. I assume there are significant downsides as it
>>>> hasn’t
>>>> been done.
>>>
>>> It would be entirely possible to do this, ultimately all that is needed
>>> is a source of heat in the firebox to create hot gases to pass through
>>> the boiler tubes and raise steam.  A tender could be converted to
>>> contain gas bottles, though methane can not easily be stored as a
>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>> only a small amount of fuel could be provided.  Propane and butane,
>>> while gases at ambient temperature and pressure, can be stored as
>>> liquids under relatively moderate pressure, as is done for things like
>>> caravan or camping fuel for cooking.
>>>
>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>> the combustion process to occur is quite long compared with light oil
>>> or gas.  Coal fireboxes are designed to provide a relatively long
>>> residence time for the combustion process to take place, with things
>>> like the brick arch and combustion chambers that facilitate this.  In a
>>> boiler burning coal, much of the actual chemical reaction releasing
>>> heat takes place above the brick arch and within the combustion
>>> chamber, so fireboxes are designed with this in mind, with water filled
>>> spaces to maximise heat transfer in those areas.  With the much shorter
>>> residence time involved in a gas flame, with a burner under a brick
>>> arch on the grate, the combustion will occur lower down, and the
>>> effectiveness of the boiler at raising steam will be impaired, with the
>>> radiant heat in the combustion zone not impinging on water-filled
>>> spaces.
>>
>> I’m not convinced by your analysis.  The firebox is completely surrounded
>> by water, apart from the grate and the fire hole door.  The only way that
>> less heat could make its way into the water would be either by heat loss
>> through the grate (which could be avoided by using refractory “coals” on
>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>> gases leaving the chimney were hotter than normal.
>
> In a coal firebox, the grate sits under the brick arch, with the airflow
> through the grate passing around the back of the brick arch and into the
> front part of the firebox/combustion chamber, then into the fire tubes.
> The brick arch does not contain water.  In a coal fire, the long
> residence time means that the actual combustion reaction oxidising fuel
> takes a relatively long time, with much of the actual combustion process
> happening in the gas path above the brick arch. Much of the heat release
> from the combustion will be radiant heat, so when combustion happens in
> this region, the radiation will impinge on the sides and top of the
> firebox in this area, on metal surfaces directly backed with water.
>
> With a gas burner, if the burnier is placed on the grate, the combustion
> will be complete before the gas passes around the brick arch.  That
> means that the radiation from the heat will, to a significant extent,
> impinge on the brick arch or grate/ashpan, which do not have water in
> them.  While this will result in them getting hot and heat transfer to
> the gases, the heat transfer from hot gas to the firebox walls and fire
> tubes is much less effective than direct radiant heating of those
> surfaces.  The result will be more heat going up the chimney.
>
>> For hydrocarbon fuels, the calorific value is approximately
>> proportional to
>> the quantity of oxygen needed for combustion.  Thus, for a given heat
>> output the amount of combustion air needed will be about the same, so the
>> volume of flue gas will be the same, and so the flue gas residence time
>> will be the same, giving the same opportunity for heat transfer.
>
> For convective heat transfer (ie from hot gas to surface), yes.  But a
> signficant part of the heat transfer is from direct radiant heat
> transfer, which will be impacted by the fact that the location of the
> combustion with a much faster burning fuel, will be in a different
> location.
>
>>> Because a major element in steam locomotive preservation in the UK is
>>> authenticity of preserving a historical locomotive, most operators and
>>> enthusiasts prefer the authenticity of coal firing, though.
>>
>> It is becoming increasingly difficult for British steam railways to
>> source
>> suitable coal.  I know that some railways were trying Russian coal, but
>> that door seems to be closing as a result of world events.
>
> I would expect a conversion to oil burning (diesel or kerosine type
> fuel) is far more straightforward in terms of fuel handling and cost,
> than gas.
>

Oil firing of steam locos is quite normal. The East African Railways
locos all ran on oil as the area has no local coal supply. I believe
quite a few of the Welsh railways use, or are intending to use, oil-firing.

--
Graeme Wall
This account not read.

On 03/03/2022 09:46, Recliner wrote:
> Bob <email@domain.com> wrote:
>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>
>>> Bob <email@domain.com> wrote:
>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>
>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>> been done.
>>>>
>>>> It would be entirely possible to do this, ultimately all that is needed
>>>> is a source of heat in the firebox to create hot gases to pass through
>>>> the boiler tubes and raise steam. A tender could be converted to
>>>> contain gas bottles, though methane can not easily be stored as a
>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>> only a small amount of fuel could be provided. Propane and butane,
>>>> while gases at ambient temperature and pressure, can be stored as
>>>> liquids under relatively moderate pressure, as is done for things like
>>>> caravan or camping fuel for cooking.
>>>>
>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>> the combustion process to occur is quite long compared with light oil
>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>> residence time for the combustion process to take place, with things
>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>> heat takes place above the brick arch and within the combustion
>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>> residence time involved in a gas flame, with a burner under a brick
>>>> arch on the grate, the combustion will occur lower down, and the
>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>> radiant heat in the combustion zone not impinging on water-filled
>>>> spaces.
>>>
>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>> by water, apart from the grate and the fire hole door. The only way that
>>> less heat could make its way into the water would be either by heat loss
>>> through the grate (which could be avoided by using refractory “coals” on
>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>> gases leaving the chimney were hotter than normal.
>>
>> In a coal firebox, the grate sits under the brick arch, with the
>> airflow through the grate passing around the back of the brick arch and
>> into the front part of the firebox/combustion chamber, then into the
>> fire tubes. The brick arch does not contain water. In a coal fire,
>> the long residence time means that the actual combustion reaction
>> oxidising fuel takes a relatively long time, with much of the actual
>> combustion process happening in the gas path above the brick arch.
>> Much of the heat release from the combustion will be radiant heat, so
>> when combustion happens in this region, the radiation will impinge on
>> the sides and top of the firebox in this area, on metal surfaces
>> directly backed with water.
>>
>> With a gas burner, if the burnier is placed on the grate, the
>> combustion will be complete before the gas passes around the brick
>> arch. That means that the radiation from the heat will, to a
>> significant extent, impinge on the brick arch or grate/ashpan, which do
>> not have water in them. While this will result in them getting hot and
>> heat transfer to the gases, the heat transfer from hot gas to the
>> firebox walls and fire tubes is much less effective than direct radiant
>> heating of those surfaces. The result will be more heat going up the
>> chimney.
>>
>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>> output the amount of combustion air needed will be about the same, so the
>>> volume of flue gas will be the same, and so the flue gas residence time
>>> will be the same, giving the same opportunity for heat transfer.
>>
>> For convective heat transfer (ie from hot gas to surface), yes. But a
>> signficant part of the heat transfer is from direct radiant heat
>> transfer, which will be impacted by the fact that the location of the
>> combustion with a much faster burning fuel, will be in a different
>> location.
>>
>>>> Because a major element in steam locomotive preservation in the UK is
>>>> authenticity of preserving a historical locomotive, most operators and
>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>
>>> It is becoming increasingly difficult for British steam railways to source
>>> suitable coal. I know that some railways were trying Russian coal, but
>>> that door seems to be closing as a result of world events.
>>
>> I would expect a conversion to oil burning (diesel or kerosine type
>> fuel) is far more straightforward in terms of fuel handling and cost,
>> than gas.
>>
>
> And refuelling is much easier, too.
>
> I wonder if smoke could be added in the same way that display aircraft like
> the Red Arrows do? A smoke generator could be used to produce smoke as and
> when needed (eg, when pulling away from a station), but kept turned off
> otherwise. You could even have coloured smoke!

IME experience an oil-burning steam engine produces more tan enough
smoke in normal operation! And a well-fired coal engine shouldn't be
producing smoke, just steam!

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 03/03/2022 09:46, Recliner wrote:
>> Bob <email@domain.com> wrote:
>>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>>
>>>> Bob <email@domain.com> wrote:
>>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>>
>>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>>> been done.
>>>>>
>>>>> It would be entirely possible to do this, ultimately all that is needed
>>>>> is a source of heat in the firebox to create hot gases to pass through
>>>>> the boiler tubes and raise steam. A tender could be converted to
>>>>> contain gas bottles, though methane can not easily be stored as a
>>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>>> only a small amount of fuel could be provided. Propane and butane,
>>>>> while gases at ambient temperature and pressure, can be stored as
>>>>> liquids under relatively moderate pressure, as is done for things like
>>>>> caravan or camping fuel for cooking.
>>>>>
>>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>>> the combustion process to occur is quite long compared with light oil
>>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>>> residence time for the combustion process to take place, with things
>>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>>> heat takes place above the brick arch and within the combustion
>>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>>> residence time involved in a gas flame, with a burner under a brick
>>>>> arch on the grate, the combustion will occur lower down, and the
>>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>>> radiant heat in the combustion zone not impinging on water-filled
>>>>> spaces.
>>>>
>>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>>> by water, apart from the grate and the fire hole door. The only way that
>>>> less heat could make its way into the water would be either by heat loss
>>>> through the grate (which could be avoided by using refractory “coals” on
>>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>>> gases leaving the chimney were hotter than normal.
>>>
>>> In a coal firebox, the grate sits under the brick arch, with the
>>> airflow through the grate passing around the back of the brick arch and
>>> into the front part of the firebox/combustion chamber, then into the
>>> fire tubes. The brick arch does not contain water. In a coal fire,
>>> the long residence time means that the actual combustion reaction
>>> oxidising fuel takes a relatively long time, with much of the actual
>>> combustion process happening in the gas path above the brick arch.
>>> Much of the heat release from the combustion will be radiant heat, so
>>> when combustion happens in this region, the radiation will impinge on
>>> the sides and top of the firebox in this area, on metal surfaces
>>> directly backed with water.
>>>
>>> With a gas burner, if the burnier is placed on the grate, the
>>> combustion will be complete before the gas passes around the brick
>>> arch. That means that the radiation from the heat will, to a
>>> significant extent, impinge on the brick arch or grate/ashpan, which do
>>> not have water in them. While this will result in them getting hot and
>>> heat transfer to the gases, the heat transfer from hot gas to the
>>> firebox walls and fire tubes is much less effective than direct radiant
>>> heating of those surfaces. The result will be more heat going up the
>>> chimney.
>>>
>>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>>> output the amount of combustion air needed will be about the same, so the
>>>> volume of flue gas will be the same, and so the flue gas residence time
>>>> will be the same, giving the same opportunity for heat transfer.
>>>
>>> For convective heat transfer (ie from hot gas to surface), yes. But a
>>> signficant part of the heat transfer is from direct radiant heat
>>> transfer, which will be impacted by the fact that the location of the
>>> combustion with a much faster burning fuel, will be in a different
>>> location.
>>>
>>>>> Because a major element in steam locomotive preservation in the UK is
>>>>> authenticity of preserving a historical locomotive, most operators and
>>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>>
>>>> It is becoming increasingly difficult for British steam railways to source
>>>> suitable coal. I know that some railways were trying Russian coal, but
>>>> that door seems to be closing as a result of world events.
>>>
>>> I would expect a conversion to oil burning (diesel or kerosine type
>>> fuel) is far more straightforward in terms of fuel handling and cost,
>>> than gas.
>>>
>>
>> And refuelling is much easier, too.
>>
>> I wonder if smoke could be added in the same way that display aircraft like
>> the Red Arrows do? A smoke generator could be used to produce smoke as and
>> when needed (eg, when pulling away from a station), but kept turned off
>> otherwise. You could even have coloured smoke!
>
> IME experience an oil-burning steam engine produces more tan enough
> smoke in normal operation! And a well-fired coal engine shouldn't be
> producing smoke, just steam!
>

My understanding is that some of the alternative sources of coal contain
more of what seem to be called volatiles, and this leads to more smoke. The
few oil fired locos I’ve seen produce lots of smoke - which led me to
contemplate butane/propane as it is cleaner burning. Producing lots of
smoke may not be acceptable by the normal population in the future.

Tweed <usenet.tweed@gmail.com> wrote:
> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> On 03/03/2022 09:46, Recliner wrote:
>>> Bob <email@domain.com> wrote:
>>>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>>>
>>>>> Bob <email@domain.com> wrote:
>>>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>>>
>>>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>>>> been done.
>>>>>>
>>>>>> It would be entirely possible to do this, ultimately all that is needed
>>>>>> is a source of heat in the firebox to create hot gases to pass through
>>>>>> the boiler tubes and raise steam. A tender could be converted to
>>>>>> contain gas bottles, though methane can not easily be stored as a
>>>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>>>> only a small amount of fuel could be provided. Propane and butane,
>>>>>> while gases at ambient temperature and pressure, can be stored as
>>>>>> liquids under relatively moderate pressure, as is done for things like
>>>>>> caravan or camping fuel for cooking.
>>>>>>
>>>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>>>> the combustion process to occur is quite long compared with light oil
>>>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>>>> residence time for the combustion process to take place, with things
>>>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>>>> heat takes place above the brick arch and within the combustion
>>>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>>>> residence time involved in a gas flame, with a burner under a brick
>>>>>> arch on the grate, the combustion will occur lower down, and the
>>>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>>>> radiant heat in the combustion zone not impinging on water-filled
>>>>>> spaces.
>>>>>
>>>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>>>> by water, apart from the grate and the fire hole door. The only way that
>>>>> less heat could make its way into the water would be either by heat loss
>>>>> through the grate (which could be avoided by using refractory “coals” on
>>>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>>>> gases leaving the chimney were hotter than normal.
>>>>
>>>> In a coal firebox, the grate sits under the brick arch, with the
>>>> airflow through the grate passing around the back of the brick arch and
>>>> into the front part of the firebox/combustion chamber, then into the
>>>> fire tubes. The brick arch does not contain water. In a coal fire,
>>>> the long residence time means that the actual combustion reaction
>>>> oxidising fuel takes a relatively long time, with much of the actual
>>>> combustion process happening in the gas path above the brick arch.
>>>> Much of the heat release from the combustion will be radiant heat, so
>>>> when combustion happens in this region, the radiation will impinge on
>>>> the sides and top of the firebox in this area, on metal surfaces
>>>> directly backed with water.
>>>>
>>>> With a gas burner, if the burnier is placed on the grate, the
>>>> combustion will be complete before the gas passes around the brick
>>>> arch. That means that the radiation from the heat will, to a
>>>> significant extent, impinge on the brick arch or grate/ashpan, which do
>>>> not have water in them. While this will result in them getting hot and
>>>> heat transfer to the gases, the heat transfer from hot gas to the
>>>> firebox walls and fire tubes is much less effective than direct radiant
>>>> heating of those surfaces. The result will be more heat going up the
>>>> chimney.
>>>>
>>>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>>>> output the amount of combustion air needed will be about the same, so the
>>>>> volume of flue gas will be the same, and so the flue gas residence time
>>>>> will be the same, giving the same opportunity for heat transfer.
>>>>
>>>> For convective heat transfer (ie from hot gas to surface), yes. But a
>>>> signficant part of the heat transfer is from direct radiant heat
>>>> transfer, which will be impacted by the fact that the location of the
>>>> combustion with a much faster burning fuel, will be in a different
>>>> location.
>>>>
>>>>>> Because a major element in steam locomotive preservation in the UK is
>>>>>> authenticity of preserving a historical locomotive, most operators and
>>>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>>>
>>>>> It is becoming increasingly difficult for British steam railways to source
>>>>> suitable coal. I know that some railways were trying Russian coal, but
>>>>> that door seems to be closing as a result of world events.
>>>>
>>>> I would expect a conversion to oil burning (diesel or kerosine type
>>>> fuel) is far more straightforward in terms of fuel handling and cost,
>>>> than gas.
>>>>
>>>
>>> And refuelling is much easier, too.
>>>
>>> I wonder if smoke could be added in the same way that display aircraft like
>>> the Red Arrows do? A smoke generator could be used to produce smoke as and
>>> when needed (eg, when pulling away from a station), but kept turned off
>>> otherwise. You could even have coloured smoke!
>>
>> IME experience an oil-burning steam engine produces more tan enough
>> smoke in normal operation! And a well-fired coal engine shouldn't be
>> producing smoke, just steam!
>>
>
> My understanding is that some of the alternative sources of coal contain
> more of what seem to be called volatiles, and this leads to more smoke. The
> few oil fired locos I’ve seen produce lots of smoke - which led me to
> contemplate butane/propane as it is cleaner burning. Producing lots of
> smoke may not be acceptable by the normal population in the future.

If you are using solid fuel with high volatiles, then it could be
worthwhile to convert the firebox to the gas producer system developed by L
D Porta.

--
Jeremy Double

On 04/03/2022 01:12, Nobody wrote:
> On 3 Mar 2022 13:34:05 GMT, Jeremy Double <jmd.nospam@btinternet.com>
> wrote:
>
>> Bob <email@domain.com> wrote:
>>> On 2022-03-03 09:46:38 +0000, Recliner said:
>>>
>>>> Bob <email@domain.com> wrote:
>>>>> On 2022-03-02 23:48:24 +0000, Jeremy Double said:
>>>>>
>>>>>> Bob <email@domain.com> wrote:
>>>>>>> On 2022-03-02 12:11:16 +0000, Tweed said:
>>>>>>>
>>>>>>>> I’ve just been reading an article about the difficulties of obtaining coal
>>>>>>>> with low volatile content. The obtainable stuff seems to produce more
>>>>>>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>>>>>>> me to ponder about gas burning instead. Could you have a propane/butane
>>>>>>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>>>>>>> low local pollution. I assume there are significant downsides as it hasn’t
>>>>>>>> been done.
>>>>>>>
>>>>>>> It would be entirely possible to do this, ultimately all that is needed
>>>>>>> is a source of heat in the firebox to create hot gases to pass through
>>>>>>> the boiler tubes and raise steam. A tender could be converted to
>>>>>>> contain gas bottles, though methane can not easily be stored as a
>>>>>>> liquid at ambient temperature, so if it stores ordinary natural gas,
>>>>>>> only a small amount of fuel could be provided. Propane and butane,
>>>>>>> while gases at ambient temperature and pressure, can be stored as
>>>>>>> liquids under relatively moderate pressure, as is done for things like
>>>>>>> caravan or camping fuel for cooking.
>>>>>>>
>>>>>>> Coal and heavy oil burn relatively slowly, that is to say the time for
>>>>>>> the combustion process to occur is quite long compared with light oil
>>>>>>> or gas. Coal fireboxes are designed to provide a relatively long
>>>>>>> residence time for the combustion process to take place, with things
>>>>>>> like the brick arch and combustion chambers that facilitate this. In a
>>>>>>> boiler burning coal, much of the actual chemical reaction releasing
>>>>>>> heat takes place above the brick arch and within the combustion
>>>>>>> chamber, so fireboxes are designed with this in mind, with water filled
>>>>>>> spaces to maximise heat transfer in those areas. With the much shorter
>>>>>>> residence time involved in a gas flame, with a burner under a brick
>>>>>>> arch on the grate, the combustion will occur lower down, and the
>>>>>>> effectiveness of the boiler at raising steam will be impaired, with the
>>>>>>> radiant heat in the combustion zone not impinging on water-filled
>>>>>>> spaces.
>>>>>>
>>>>>> I’m not convinced by your analysis. The firebox is completely surrounded
>>>>>> by water, apart from the grate and the fire hole door. The only way that
>>>>>> less heat could make its way into the water would be either by heat loss
>>>>>> through the grate (which could be avoided by using refractory “coals” on
>>>>>> the grate, like a scaled up version of a coal-effect gas fire), or if the
>>>>>> gases leaving the chimney were hotter than normal.
>>>>>
>>>>> In a coal firebox, the grate sits under the brick arch, with the
>>>>> airflow through the grate passing around the back of the brick arch and
>>>>> into the front part of the firebox/combustion chamber, then into the
>>>>> fire tubes. The brick arch does not contain water. In a coal fire,
>>>>> the long residence time means that the actual combustion reaction
>>>>> oxidising fuel takes a relatively long time, with much of the actual
>>>>> combustion process happening in the gas path above the brick arch.
>>>>> Much of the heat release from the combustion will be radiant heat, so
>>>>> when combustion happens in this region, the radiation will impinge on
>>>>> the sides and top of the firebox in this area, on metal surfaces
>>>>> directly backed with water.
>>>>>
>>>>> With a gas burner, if the burnier is placed on the grate, the
>>>>> combustion will be complete before the gas passes around the brick
>>>>> arch. That means that the radiation from the heat will, to a
>>>>> significant extent, impinge on the brick arch or grate/ashpan, which do
>>>>> not have water in them. While this will result in them getting hot and
>>>>> heat transfer to the gases, the heat transfer from hot gas to the
>>>>> firebox walls and fire tubes is much less effective than direct radiant
>>>>> heating of those surfaces. The result will be more heat going up the
>>>>> chimney.
>>>>>
>>>>>> For hydrocarbon fuels, the calorific value is approximately proportional to
>>>>>> the quantity of oxygen needed for combustion. Thus, for a given heat
>>>>>> output the amount of combustion air needed will be about the same, so the
>>>>>> volume of flue gas will be the same, and so the flue gas residence time
>>>>>> will be the same, giving the same opportunity for heat transfer.
>>>>>
>>>>> For convective heat transfer (ie from hot gas to surface), yes. But a
>>>>> signficant part of the heat transfer is from direct radiant heat
>>>>> transfer, which will be impacted by the fact that the location of the
>>>>> combustion with a much faster burning fuel, will be in a different
>>>>> location.
>>>>>
>>>>>>> Because a major element in steam locomotive preservation in the UK is
>>>>>>> authenticity of preserving a historical locomotive, most operators and
>>>>>>> enthusiasts prefer the authenticity of coal firing, though.
>>>>>>
>>>>>> It is becoming increasingly difficult for British steam railways to source
>>>>>> suitable coal. I know that some railways were trying Russian coal, but
>>>>>> that door seems to be closing as a result of world events.
>>>>>
>>>>> I would expect a conversion to oil burning (diesel or kerosine type
>>>>> fuel) is far more straightforward in terms of fuel handling and cost,
>>>>> than gas.
>>>>>
>>>>
>>>> And refuelling is much easier, too.
>>>>
>>>> I wonder if smoke could be added in the same way that display aircraft like
>>>> the Red Arrows do? A smoke generator could be used to produce smoke as and
>>>> when needed (eg, when pulling away from a station), but kept turned off
>>>> otherwise. You could even have coloured smoke!
>>>
>>> A well-run steam locomotive burning coal should not produce much
>>> visible smoke. If you see smoke it's because the fireman is not doing
>>> his job right. Steam exhaust from the blastpipe will be unaffected by
>>> the fuel source.
>>
>> You can sometimes see when the fireman has put coal on the fire, because
>> the exhaust briefly becomes a darker shade of grey.
>
> Is that an inadvertent inverse Procul Harum quote?

With a face at first just ghastly?

--
Graeme Wall
This account not read.

Mark Goodge <usenet@listmail.good-stuff.co.uk> wrote:
> On Wed, 2 Mar 2022 12:11:16 -0000 (UTC), Tweed <usenet.tweed@gmail.com>
> wrote:
>
>> I’ve just been reading an article about the difficulties of obtaining coal
>> with low volatile content. The obtainable stuff seems to produce more
>> smoke. I’ve read about converting steam locos to oil burning, but this led
>> me to ponder about gas burning instead. Could you have a propane/butane
>> bottle in the tender and a suitable burner in the grate? The advantages are
>> low local pollution. I assume there are significant downsides as it hasn’t
>> been done.
>
> Oil-fired steam locomotives are certainly a thing, and not at all new.
> See, for example, http://www.greatwestern.org.uk/m_in_gwr_oil_fire.htm
> for examples in the UK, and in parts of the US where oil was plentiful
> but coal more scarce they were used as early as the 1920s.
>
> Gas would be somewhat more complex, though, due to the need to store it
> under pressure (or as a liquid and then converted to gas on the move)
> and because the burning qualities of gas are quite different to those of
> oil or coal. So I don't think you could convert an existing coal-fired
> loco to gas in the same way that it's possible to convert it to oil - it
> would need to be a new design. But, if you were starting from scratch
> with a new design to use gas, then you wouldn't use steam as the
> transmission. Gas turbine locomotives with electric or mechanical
> transission have been around since the 1950s. But, with few exceptions,
> they are neither as effective nor as efficient as diesel-electric
> locomotives, so they remain a niche use.
>

In a way the set up would be less complicated than for oil - basically just
a big barbecue, surely? - whereas oil firing AIUI involves steam being used
to atomise the oil for combustion, with two separate controls for that.

Anna Noyd-Dryver

Tweed <usenet.tweed@gmail.com> wrote:
> Marland <gemehabal@btinternet.co.uk> wrote:
>> Tweed <usenet.tweed@gmail.com> wrote:
>>> I’ve just been reading an article about the difficulties of obtaining coal
>>> with low volatile content. The obtainable stuff seems to produce more
>>> smoke. I’ve read about converting steam locos to oil burning, but this led
>>> me to ponder about gas burning instead. Could you have a propane/butane
>>> bottle in the tender and a suitable burner in the grate? The advantages are
>>> low local pollution. I assume there are significant downsides as it hasn’t
>>> been done.
>>>
>>>
>>>
>>
>> Its certainly done already in the Model Engineering size scales though more
>> the smaller ones up to 5” gauge . I would imagine scaling up to full size
>> or even narrow gauge could be challenging.
>> One thing where gas (and oil) firing differs vastly from solid fuel is the
>> heat reserve in the fire itself
>> Gas and oil is used instantly and has to be capable of responding to demand
>> instantly as the boiler is depleted so suits large locomotives with larger
>> boilers where the boiler is storing by pressure power for any extra demand
>> like an adverse gradient. In contrast a large bed of coal can be prepared
>> in advance so the coal is just glowing at red heat but when required can be
>> brought very quickly to white heat by the draught and increase its heat
>> output quickly.
>>
>> I did discover this video of a miniature railway locomotive in the states
>> that is propane powered
>> < https://youtu.be/MTnDS7MKkdw>
>>
>> A few minutes in the camera focuses on the firebox, that looks a pretty
>> substantial pipe to supply the gas required, how large would one for say a
>> typical UK std gauge engine need to be , and I wonder what range would a
>> tank installed in a bunker or tender give between refills.
>>
>> GH
>>
>>
>>
>
> Couldn’t you just turn up the gas supply to provide instant extra heat?
> Much easier than having to preplan building up a fire.
>
>

To a certain extent I think the coal fire will be self-managing - sitting
in a station it'll sit there glowing red, pull away and the draught from
the blastpipe will liven that same fire up to white hot. With oil or gas,
the fireman has to constantly manage that process.

An example, albeit with smaller trains: I used to work at a railway museum
which has a 1 mile 7.25" gauge line. The coal fires are tended at the
station while the passengers board, and untouched all the way around the
circuit - which includes two reasonably big climbs. I think they might not
even carry coal on the loco (maybe a small amount).

We had an oil-fired loco on loan. It wasn't popular because it would run
out of steam unless the driver was constantly adjusting the fire during the
run - first for the gentle trundle, then the climb, immediate fall, a lot
more gentle trundle, then the climb and fall again and finally more
trundle.

We barely used that loco while it was on loan and we didn't keep it!

Anna Noyd-Dryver

Nobody <jock@soccer.com> wrote:
> On Fri, 4 Mar 2022 07:53:11 +0000, Graeme Wall
> <rail@greywall.demon.co.uk> wrote:
..
>>>>
>>>> You can sometimes see when the fireman has put coal on the fire, because
>>>> the exhaust briefly becomes a darker shade of grey.
>>>
>>> Is that an inadvertent inverse Procul Harum quote?
>>
Well it gave me an earworm, but as they go it isn’t too bad.

>> With a face at first just ghastly?
>
> <guffaw>
>
> But first, RIP the recently deceased Gary Brooker... so ghostly,
> please.
>
> Still, you must mean this vid:
>
> <https://www.youtube.com/watch?v=Mb3iPP-tHdA>
>

And still no one really knows what the song was about.

GH

Graeme Wall <rail@greywall.demon.co.uk> wrote in uk.railway:

> IME experience an oil-burning steam engine produces more tan enough
> smoke in normal operation! And a well-fired coal engine shouldn't be
> producing smoke, just steam!

Doesn't say much for this one, then:

https://www.cynic.org.uk/photos/D50/large/103ncd50/dsc_7343.jpg

On 05/03/2022 19:55, Robin Stevens wrote:
> Graeme Wall <rail@greywall.demon.co.uk> wrote in uk.railway:
>
>> IME experience an oil-burning steam engine produces more tan enough
>> smoke in normal operation! And a well-fired coal engine shouldn't be
>> producing smoke, just steam!
>
> Doesn't say much for this one, then:
>
> https://www.cynic.org.uk/photos/D50/large/103ncd50/dsc_7343.jpg
>
>

Something tells me they aren't using Welsh steam coal!

--
Graeme Wall
This account not read.

In message <svqlbv$2bq$1@dont-email.me>, at 15:03:27 on Thu, 3 Mar 2022,
Recliner <recliner.usenet@gmail.com> remarked:
>Roland Perry <roland@perry.co.uk> wrote:
>> In message <svq60v$6ef$1@dont-email.me>, at 11:41:35 on Thu, 3 Mar 2022,
>> Bob <email@domain.com> remarked:
>>
>>> A well-run steam locomotive burning coal should not produce much
>>> visible smoke. If you see smoke it's because the fireman is not doing
>>> his job right. Steam exhaust from the blastpipe will be unaffected by
>>> the fuel source.
>>
>> Quite a bit of smoke, and *lots* of steam!
>>
>> https://youtu.be/9qyZnYyqoKI
>>
>> [Apologies for video quality, it's getting on for ten years old]
>
>It's funny, I was going to post that Tangmere always seems very smokey. It
>can't be because of an individual fireman, so it must be something about
>the loco itself.

Thumbnail of Clun Castle last weekend.

http://www.perry.co.uk/images/clun_castle_2022.jpg
--
Roland Perry