https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf

<martin.coffee@round-midnight.org.uk> wrote in message
news:sv0j6e$oog$1@dont-email.me...
> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf

The report mentions "sanding systems on train 1L53". Does an emergency brake
application automatically apply sand in front of some/all of the braked
wheels, or is the sand application something that the driver has to initiate
manually? If sand was applied starting twelve seconds after the driver made
his first service-level brake application, I'm surprised the speed of the
train wasn't reduced more. What proportion of the braked wheels get a sand
application? Is it just the leading wheels, with the expectation that sand
will adhere to any leaf mulch and so benefit all the other braked wheels as
well?

What sort of indication does a driver get of wheelslide and/or WSP
activation? Is it reliant on the driver deciding he isn't slowing down as
much as he expects, or does he get a positive "wheels-locked" or wheelslide
warning to tell him "go into emergency braking mode ASAP"? Does WSP activate
at *any* braking level if it detects that some wheels have stopped (ie are
sliding) while other unbraked ones are still turning, or does it only
activate once the driver moves the brake lever to the emergency position?
Six seconds to go from service to full and then six more seconds to go from
full to emergency *sounds* a long time. It amounts to (186 km/hr / 3600) *
12 = 620 metres or a little over half the remaining distance. Are these
timings typical in a situation where wheelside is suspected?

<martin.coffee@round-midnight.org.uk> wrote:
> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf
>

Three paras stand out:

42 With reference to the RHTT programme, the Wessex route Autumn working
arrangements document stated that ‘Wessex aspire for all routes to be
covered once in 24 hours throughout the Autumn period.’ On weekdays (Monday
to Friday) two RHTT were scheduled to operate over each section of line
each day. The working arrangements document stated that this was ‘to
maximise the chance of each site being treated at least once [every 24
hours]. One set of circuits run at weekends.’

43 On the day of the accident (a Sunday), the RHTT that was due to treat
Salisbury Tunnel Junction on the down main line at 17:03 hrs had not yet
passed through the area because it had been rescheduled. This rescheduling
meant that it would (but for the accident) have passed the junction at
around 23:00 hrs. The revised schedule, which was a consequence of planned
engineering work between Southampton and Brockenhurst, meant that there
would have been an interval of 36 hours between the RHTT runs over the
weekend.

44 The last RHTT to run over the junction passed over it at 11:06 hrs on 30
October, around 32 hours before the accident occurred. This RHTT delivered
high-pressure water jetting, and although it could apply adhesion modifier
gel, it was not required to do so on this section of track.

—————

It's a pity that the testing and roll-out of DVRS has been so slow, as it
would almost certainly have prevented this crash had it been fitted to the
159.

"Recliner" <recliner.usenet@gmail.com> wrote in message
news:sv12hl$j0l$1@dont-email.me...
> It's a pity that the testing and roll-out of DVRS has been so slow, as it
> would almost certainly have prevented this crash had it been fitted to the
> 159.

What's DVRS in this context? https://acronyms.thefreedictionary.com/DVRS
lists various phrases but not one that is relevant.

NY <me@privacy.invalid> wrote:
> "Recliner" <recliner.usenet@gmail.com> wrote in message
> news:sv12hl$j0l$1@dont-email.me...
>> It's a pity that the testing and roll-out of DVRS has been so slow, as it
>> would almost certainly have prevented this crash had it been fitted to the
>> 159.
>
> What's DVRS in this context? https://acronyms.thefreedictionary.com/DVRS
> lists various phrases but not one that is relevant.
>

Double Variable Rate Sanders

See https://www.railengineer.co.uk/get-a-grip/

On 21/02/2022 22:08, Recliner wrote:
> <martin.coffee@round-midnight.org.uk> wrote:
>> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf
>>
>
> Three paras stand out:
>
> 42 With reference to the RHTT programme, the Wessex route Autumn working
> arrangements document stated that ‘Wessex aspire for all routes to be
> covered once in 24 hours throughout the Autumn period.’ On weekdays (Monday
> to Friday) two RHTT were scheduled to operate over each section of line
> each day. The working arrangements document stated that this was ‘to
> maximise the chance of each site being treated at least once [every 24
> hours]. One set of circuits run at weekends.’
>
> 43 On the day of the accident (a Sunday), the RHTT that was due to treat
> Salisbury Tunnel Junction on the down main line at 17:03 hrs had not yet
> passed through the area because it had been rescheduled. This rescheduling
> meant that it would (but for the accident) have passed the junction at
> around 23:00 hrs. The revised schedule, which was a consequence of planned
> engineering work between Southampton and Brockenhurst, meant that there
> would have been an interval of 36 hours between the RHTT runs over the
> weekend.
>
> 44 The last RHTT to run over the junction passed over it at 11:06 hrs on 30
> October, around 32 hours before the accident occurred. This RHTT delivered
> high-pressure water jetting, and although it could apply adhesion modifier
> gel, it was not required to do so on this section of track.

I presume the period of 24 hours has been found empirically to be the
longest that still gives an acceptable level of adhesion if a train uses
the track just before RHTT train is due, ie with just under 24 hours of
grot build-up.

Is wheelslide on braking a new phenomenon, or did it also exist with
loco-hauled trains (as opposed to multiple units) with their heavier
axle loads on the loco's driving/braked wheels. Did tyre brakes on steam
locos help to keep the tyres and hence the rails more clear of leaf
mulch? Did fewer trees on cuttings in the old days help a lot? Or has it
always been a problem?

NY <me@privacy.net> wrote:

> Is wheelslide on braking a new phenomenon, or did it also exist with
> loco-hauled trains (as opposed to multiple units) with their heavier
> axle loads on the loco's driving/braked wheels. Did tyre brakes on steam
> locos help to keep the tyres and hence the rails more clear of leaf
> mulch? Did fewer trees on cuttings in the old days help a lot? Or has it
> always been a problem?
>

Interesting to see photos of the site 50 years as on this link and others
that can be accessed from it
<https://www.flickr.com/photos/96859208@N07/10873403504/in/photostream/>

The photos of the crash show that tree growth since then has been
considerable.

Some disk braked stock has been fitted with some wheel tread brake blocks
to act as scrubbers
but overall the number of such wheels passing over a section of track must
be much less than in the past. Fully fitted freights with four wheeled
wagons are very rare now . I wonder going back to much earlier periods when
many goods trains only had brakes on the locomotive and brake van if there
were problems, OTOH they travelled much slower than modern services,the SWR
train was travelling at a speed above our 70mph motorway limit as it
approached the signals for the junction and normally slows down or stops
from that pace without drama if required to do so.

GH

On 22/02/2022 00:53, NY wrote:
> On 21/02/2022 22:08, Recliner wrote:
>> <martin.coffee@round-midnight.org.uk> wrote:
>>> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf
>>>
>>>
>>
>> Three paras stand out:
>>
>> 42 With reference to the RHTT programme, the Wessex route Autumn working
>> arrangements document stated that ‘Wessex aspire for all routes to be
>> covered once in 24 hours throughout the Autumn period.’ On weekdays
>> (Monday
>> to Friday) two RHTT were scheduled to operate over each section of line
>> each day. The working arrangements document stated that this was ‘to
>> maximise the chance of each site being treated at least once [every 24
>> hours]. One set of circuits run at weekends.’
>>
>> 43 On the day of the accident (a Sunday), the RHTT that was due to treat
>> Salisbury Tunnel Junction on the down main line at 17:03 hrs had not yet
>> passed through the area because it had been rescheduled. This
>> rescheduling
>> meant that it would (but for the accident) have passed the junction at
>> around 23:00 hrs. The revised schedule, which was a consequence of
>> planned
>> engineering work between Southampton and Brockenhurst, meant that there
>> would have been an interval of 36 hours between the RHTT runs over the
>> weekend.
>>
>> 44 The last RHTT to run over the junction passed over it at 11:06 hrs
>> on 30
>> October, around 32 hours before the accident occurred. This RHTT
>> delivered
>> high-pressure water jetting, and although it could apply adhesion
>> modifier
>> gel, it was not required to do so on this section of track.
>
> I presume the period of 24 hours has been found empirically to be the
> longest that still gives an acceptable level of adhesion if a train uses
> the track just before RHTT train is due, ie with just under 24 hours of
> grot build-up.
>
> Is wheelslide on braking a new phenomenon, or did it also exist with
> loco-hauled trains (as opposed to multiple units) with their heavier
> axle loads on the loco's driving/braked wheels. Did tyre brakes on steam
> locos help to keep the tyres and hence the rails more clear of leaf
> mulch? Did fewer trees on cuttings in the old days help a lot? Or has it
> always been a problem?

Yes, there were slipping problems in steam days, not just from leaves.
Just look at videos of Bullied Pacifics trying to start a heavy train
out of Waterloo!
https://www.youtube.com/watch?v=iKzRNrDH5AU
https://www.youtube.com/watch?v=jWNa2k0PSsM

As Graeme says, speeds were much slower.

--
Colin

On 22/02/2022 10:12, ColinR wrote:
> On 22/02/2022 00:53, NY wrote:
>> On 21/02/2022 22:08, Recliner wrote:
>>> <martin.coffee@round-midnight.org.uk> wrote:
>>>> https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junction.pdf
>>>>
>>>>
>>>
>>> Three paras stand out:
>>>
>>> 42 With reference to the RHTT programme, the Wessex route Autumn working
>>> arrangements document stated that ‘Wessex aspire for all routes to be
>>> covered once in 24 hours throughout the Autumn period.’ On weekdays
>>> (Monday
>>> to Friday) two RHTT were scheduled to operate over each section of line
>>> each day. The working arrangements document stated that this was ‘to
>>> maximise the chance of each site being treated at least once [every 24
>>> hours]. One set of circuits run at weekends.’
>>>
>>> 43 On the day of the accident (a Sunday), the RHTT that was due to treat
>>> Salisbury Tunnel Junction on the down main line at 17:03 hrs had not yet
>>> passed through the area because it had been rescheduled. This
>>> rescheduling
>>> meant that it would (but for the accident) have passed the junction at
>>> around 23:00 hrs. The revised schedule, which was a consequence of
>>> planned
>>> engineering work between Southampton and Brockenhurst, meant that there
>>> would have been an interval of 36 hours between the RHTT runs over the
>>> weekend.
>>>
>>> 44 The last RHTT to run over the junction passed over it at 11:06 hrs
>>> on 30
>>> October, around 32 hours before the accident occurred. This RHTT
>>> delivered
>>> high-pressure water jetting, and although it could apply adhesion
>>> modifier
>>> gel, it was not required to do so on this section of track.
>>
>> I presume the period of 24 hours has been found empirically to be the
>> longest that still gives an acceptable level of adhesion if a train
>> uses the track just before RHTT train is due, ie with just under 24
>> hours of grot build-up.
>>
>> Is wheelslide on braking a new phenomenon, or did it also exist with
>> loco-hauled trains (as opposed to multiple units) with their heavier
>> axle loads on the loco's driving/braked wheels. Did tyre brakes on
>> steam locos help to keep the tyres and hence the rails more clear of
>> leaf mulch? Did fewer trees on cuttings in the old days help a lot? Or
>> has it always been a problem?
>
> Yes, there were slipping problems in steam days, not just from leaves.
> Just look at videos of Bullied Pacifics trying to start a heavy train
> out of Waterloo!
> https://www.youtube.com/watch?v=iKzRNrDH5AU
> https://www.youtube.com/watch?v=jWNa2k0PSsM
>
> As Graeme says, speeds were much slower.
>
The one thing I noticed is that the circumstances are identical to an
event in Sunningdale about 25 years ago. The RHTT had not run and a
train on the Chertsey branch slid onto the main line. Fortunately no
other train was involved.

The rules should be change to be changed so that normal trains are
banned if the RHTT has not run within the prescribed time.

In message <sv0j6e$oog$1@dont-email.me>, at 17:46:54 on Mon, 21 Feb
2022, martin.coffee@round-midnight.org.uk remarked:

>https://assets.publishing.service.gov.uk/government/uploads/system/uploa
>ds/attachment_data/file/1055846/IR012022_220221_Salisbury_Tunnel_Junctio
>n.pdf

I didn't get my notification for this until 8.30am today.
--
Roland Perry

On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
> The  one thing I noticed is that the circumstances are identical to an
> event in Sunningdale about 25 years ago.  The RHTT had not run and a
> train on the Chertsey branch slid onto the main line.  Fortunately no
> other train was involved.
>
> The rules should be change to be changed so that normal trains are
> banned if the RHTT has not run within the prescribed time.

Perhaps they could get away with asking drivers to travel below the
normal speed limit, as they do in extreme heat or other unhelpful
weather conditions, and to be especially cautious approaching junctions
even if it results in late running.

On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:

>On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>> The  one thing I noticed is that the circumstances are identical to an
>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>> train on the Chertsey branch slid onto the main line.  Fortunately no
>> other train was involved.
>>
>> The rules should be change to be changed so that normal trains are
>> banned if the RHTT has not run within the prescribed time.
>
>Perhaps they could get away with asking drivers to travel below the
>normal speed limit, as they do in extreme heat or other unhelpful
>weather conditions, and to be especially cautious approaching junctions
>even if it results in late running.

In this case, the train would have had to be travelling a *lot* slower than normal to avoid the collision, let alone a
SPAD. With almost no friction, almost any speed could lead to a SPAD; normal autumnal defensive driving wouldn't have
been enough.

The SWR train was travelling at 86 mph at the start of braking, and between 52 and 56 mph at the point of collision,
more than a mile away. To have been able to stop at the red signal, it would have had to be cruising at less than 30
mph, rather than the usual 90 mph.

In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
2022, Certes <none@nowhere.net> remarked:
>On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:

>> The  one thing I noticed is that the circumstances are identical to
>>an event in Sunningdale about 25 years ago.  The RHTT had not run and
>>a train on the Chertsey branch slid onto the main line.  Fortunately
>>no other train was involved.

>> The rules should be change to be changed so that normal trains are
>>banned if the RHTT has not run within the prescribed time.
>
>Perhaps they could get away with asking drivers to travel below the
>normal speed limit, as they do in extreme heat or other unhelpful
>weather conditions, and to be especially cautious approaching junctions
>even if it results in late running.

Reading between the lines (sorry) I think they are not yet convinced the
driver was being sufficiently defensive, and are looking at why that
might be the case.
--
Roland Perry

On 22/02/2022 13:13, Roland Perry wrote:
> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
> 2022, Certes <none@nowhere.net> remarked:
>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>
>>> The  one thing I noticed is that the circumstances are identical to
>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>> and a  train on the Chertsey branch slid onto the main line.
>>> Fortunately no  other train was involved.
>
>>>  The rules should be change to be changed so that normal trains are
>>> banned if the RHTT has not run within the prescribed time.
>>
>> Perhaps they could get away with asking drivers to travel below the
>> normal speed limit, as they do in extreme heat or other unhelpful
>> weather conditions, and to be especially cautious approaching junctions
>> even if it results in late running.
>
> Reading between the lines (sorry) I think they are not yet convinced the
> driver was being sufficiently defensive, and are looking at why that
> might be the case.

What evidence do you have for that statement?

On Tue, 22 Feb 2022 13:25:27 +0000, martin.coffee@round-midnight.org.uk wrote:

>On 22/02/2022 13:13, Roland Perry wrote:
>> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
>> 2022, Certes <none@nowhere.net> remarked:
>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>
>>>> The  one thing I noticed is that the circumstances are identical to
>>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>>> and a  train on the Chertsey branch slid onto the main line.
>>>> Fortunately no  other train was involved.
>>
>>>>  The rules should be change to be changed so that normal trains are
>>>> banned if the RHTT has not run within the prescribed time.
>>>
>>> Perhaps they could get away with asking drivers to travel below the
>>> normal speed limit, as they do in extreme heat or other unhelpful
>>> weather conditions, and to be especially cautious approaching junctions
>>> even if it results in late running.
>>
>> Reading between the lines (sorry) I think they are not yet convinced the
>> driver was being sufficiently defensive, and are looking at why that
>> might be the case.
>
>What evidence do you have for that statement?

I agree with Roland on this. These paras on p14 justify his suggestion:

• Consider the behaviour of both trains during and following the collision and the
damage caused to each

• Consider the actions taken on the day of the accident to manage the risk of low
adhesion given the time of year and prevailing weather conditions

• Consider the actions of the driver of 1L53 and any factors which may have
influenced them

• Consider South Western Railway's policies and processes relating to operating
trains in conditions of low wheel/rail adhesion including the dissemination and
responses to information

In message <gun91hhhpihfroc3fuvohjquqra44k38s7@4ax.com>, at 13:14:42 on
Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:
>
>>On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>> The  one thing I noticed is that the circumstances are identical to an
>>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>>> train on the Chertsey branch slid onto the main line.  Fortunately no
>>> other train was involved.
>>>
>>> The rules should be change to be changed so that normal trains are
>>> banned if the RHTT has not run within the prescribed time.
>>
>>Perhaps they could get away with asking drivers to travel below the
>>normal speed limit, as they do in extreme heat or other unhelpful
>>weather conditions, and to be especially cautious approaching junctions
>>even if it results in late running.
>
>In this case, the train would have had to be travelling a *lot* slower
>than normal to avoid the collision, let alone a
>SPAD. With almost no friction, almost any speed could lead to a SPAD;
>normal autumnal defensive driving wouldn't have
>been enough.
>
>The SWR train was travelling at 86 mph at the start of braking, and
>between 52 and 56 mph at the point of collision, more than a mile away.
>To have been able to stop at the red signal, it would have had to be
>cruising at less than 30 mph, rather than the usual 90 mph.

It didn't need to stop *at* the red signal, rather than just soon enough
not to foul the junction. [To avoid the accident, if not a SPAD report]
--
Roland Perry

On 22/02/2022 13:30, Recliner wrote:
> On Tue, 22 Feb 2022 13:25:27 +0000, martin.coffee@round-midnight.org.uk wrote:
>
>> On 22/02/2022 13:13, Roland Perry wrote:
>>> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
>>> 2022, Certes <none@nowhere.net> remarked:
>>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>
>>>>> The  one thing I noticed is that the circumstances are identical to
>>>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>>>> and a  train on the Chertsey branch slid onto the main line.
>>>>> Fortunately no  other train was involved.
>>>
>>>>>  The rules should be change to be changed so that normal trains are
>>>>> banned if the RHTT has not run within the prescribed time.
>>>>
>>>> Perhaps they could get away with asking drivers to travel below the
>>>> normal speed limit, as they do in extreme heat or other unhelpful
>>>> weather conditions, and to be especially cautious approaching junctions
>>>> even if it results in late running.
>>>
>>> Reading between the lines (sorry) I think they are not yet convinced the
>>> driver was being sufficiently defensive, and are looking at why that
>>> might be the case.
>>
>> What evidence do you have for that statement?
>
> I agree with Roland on this. These paras on p14 justify his suggestion:
>
> • Consider the behaviour of both trains during and following the collision and the
> damage caused to each
>
> • Consider the actions taken on the day of the accident to manage the risk of low
> adhesion given the time of year and prevailing weather conditions
>
> • Consider the actions of the driver of 1L53 and any factors which may have
> influenced them
>
> • Consider South Western Railway's policies and processes relating to operating
> trains in conditions of low wheel/rail adhesion including the dissemination and
> responses to information

I don't think there is anything in there out of the RAIB's norms. I see
nothing to support any reading between the the lines.

On Tue, 22 Feb 2022 13:45:29 +0000, Roland Perry <roland@perry.co.uk> wrote:

>In message <gun91hhhpihfroc3fuvohjquqra44k38s7@4ax.com>, at 13:14:42 on
>Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:
>>
>>>On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>> The  one thing I noticed is that the circumstances are identical to an
>>>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>>>> train on the Chertsey branch slid onto the main line.  Fortunately no
>>>> other train was involved.
>>>>
>>>> The rules should be change to be changed so that normal trains are
>>>> banned if the RHTT has not run within the prescribed time.
>>>
>>>Perhaps they could get away with asking drivers to travel below the
>>>normal speed limit, as they do in extreme heat or other unhelpful
>>>weather conditions, and to be especially cautious approaching junctions
>>>even if it results in late running.
>>
>>In this case, the train would have had to be travelling a *lot* slower
>>than normal to avoid the collision, let alone a
>>SPAD. With almost no friction, almost any speed could lead to a SPAD;
>>normal autumnal defensive driving wouldn't have
>>been enough.
>>
>>The SWR train was travelling at 86 mph at the start of braking, and
>>between 52 and 56 mph at the point of collision, more than a mile away.
>>To have been able to stop at the red signal, it would have had to be
>>cruising at less than 30 mph, rather than the usual 90 mph.
>
>It didn't need to stop *at* the red signal, rather than just soon enough
>not to foul the junction. [To avoid the accident, if not a SPAD report]

The aim would be to avoid all SPADs, not just collisions. A SPAD pretty much shuts down the railway for an extended
period.

In message <sv2qam$iiq$1@dont-email.me>, at 14:00:54 on Tue, 22 Feb
2022, martin.coffee@round-midnight.org.uk remarked:
>On 22/02/2022 13:30, Recliner wrote:
>> On Tue, 22 Feb 2022 13:25:27 +0000,
>>martin.coffee@round-midnight.org.uk wrote:
>>
>>> On 22/02/2022 13:13, Roland Perry wrote:
>>>> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
>>>> 2022, Certes <none@nowhere.net> remarked:
>>>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>>
>>>>>> The  one thing I noticed is that the circumstances are identical to
>>>>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>>>>> and a  train on the Chertsey branch slid onto the main line.
>>>>>> Fortunately no  other train was involved.
>>>>
>>>>>>  The rules should be change to be changed so that normal trains are
>>>>>> banned if the RHTT has not run within the prescribed time.
>>>>>
>>>>> Perhaps they could get away with asking drivers to travel below the
>>>>> normal speed limit, as they do in extreme heat or other unhelpful
>>>>> weather conditions, and to be especially cautious approaching junctions
>>>>> even if it results in late running.
>>>>
>>>> Reading between the lines (sorry) I think they are not yet convinced the
>>>> driver was being sufficiently defensive, and are looking at why that
>>>> might be the case.
>>>
>>> What evidence do you have for that statement?
>> I agree with Roland on this. These paras on p14 justify his
>>suggestion:
>> • Consider the behaviour of both trains during and following the
>>collision and the
>> damage caused to each
>> • Consider the actions taken on the day of the accident to
>>manage the risk of low
>> adhesion given the time of year and prevailing weather conditions
>> • Consider the actions of the driver of 1L53 and any factors
>>which may have
>> influenced them
>> • Consider South Western Railway's policies and processes
>>relating to operating
>> trains in conditions of low wheel/rail adhesion including the
>>dissemination and
>> responses to information
>
>I don't think there is anything in there out of the RAIB's norms. I see
>nothing to support any reading between the the lines.

See also:

Train driving
===========

37 OTDR data shows that train 1L53 was travelling within the permitted
speed as the train approached Salisbury Tunnel Junction. RAIB's
investigation will continue to consider the driver's actions and factors
that may have influenced them, including the industry's arrangements for
advising drivers about poor adhesion conditions and the guidance and
instructions relating to reporting low adhesion and driving in such
conditions.
--
Roland Perry

In message <khr91h9hnidr81cdp58bq1pa71nvgs16ol@4ax.com>, at 14:08:31 on
Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>On Tue, 22 Feb 2022 13:45:29 +0000, Roland Perry <roland@perry.co.uk> wrote:
>
>>In message <gun91hhhpihfroc3fuvohjquqra44k38s7@4ax.com>, at 13:14:42 on
>>Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>>On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:
>>>
>>>>On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>>> The  one thing I noticed is that the circumstances are identical to an
>>>>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>>>>> train on the Chertsey branch slid onto the main line.  Fortunately no
>>>>> other train was involved.
>>>>>
>>>>> The rules should be change to be changed so that normal trains are
>>>>> banned if the RHTT has not run within the prescribed time.
>>>>
>>>>Perhaps they could get away with asking drivers to travel below the
>>>>normal speed limit, as they do in extreme heat or other unhelpful
>>>>weather conditions, and to be especially cautious approaching junctions
>>>>even if it results in late running.
>>>
>>>In this case, the train would have had to be travelling a *lot* slower
>>>than normal to avoid the collision, let alone a
>>>SPAD. With almost no friction, almost any speed could lead to a SPAD;
>>>normal autumnal defensive driving wouldn't have
>>>been enough.
>>>
>>>The SWR train was travelling at 86 mph at the start of braking, and
>>>between 52 and 56 mph at the point of collision, more than a mile away.
>>>To have been able to stop at the red signal, it would have had to be
>>>cruising at less than 30 mph, rather than the usual 90 mph.
>>
>>It didn't need to stop *at* the red signal, rather than just soon enough
>>not to foul the junction. [To avoid the accident, if not a SPAD report]
>
>The aim would be to avoid all SPADs, not just collisions. A SPAD pretty
>much shuts down the railway for an extended period.

Indeed, and there are other hints that perhaps signallers could also
have done something to proactively slow the trains there, given the
prevailing conditions. But preventing a collision is more important and
at least gets a Silver medal.
--
Roland Perry

On 22/02/2022 14:29, Roland Perry wrote:
> In message <sv2qam$iiq$1@dont-email.me>, at 14:00:54 on Tue, 22 Feb
> 2022, martin.coffee@round-midnight.org.uk remarked:
>> On 22/02/2022 13:30, Recliner wrote:
>>> On Tue, 22 Feb 2022 13:25:27 +0000,
>>> martin.coffee@round-midnight.org.uk wrote:
>>>
>>>> On 22/02/2022 13:13, Roland Perry wrote:
>>>>> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
>>>>> 2022, Certes <none@nowhere.net> remarked:
>>>>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>>>
>>>>>>> The  one thing I noticed is that the circumstances are identical to
>>>>>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>>>>>> and a  train on the Chertsey branch slid onto the main line.
>>>>>>> Fortunately no  other train was involved.
>>>>>
>>>>>>>   The rules should be change to be changed so that normal trains are
>>>>>>> banned if the RHTT has not run within the prescribed time.
>>>>>>
>>>>>> Perhaps they could get away with asking drivers to travel below the
>>>>>> normal speed limit, as they do in extreme heat or other unhelpful
>>>>>> weather conditions, and to be especially cautious approaching
>>>>>> junctions
>>>>>> even if it results in late running.
>>>>>
>>>>> Reading between the lines (sorry) I think they are not yet
>>>>> convinced the
>>>>> driver was being sufficiently defensive, and are looking at why that
>>>>> might be the case.
>>>>
>>>> What evidence do you have for that statement?
>>>  I agree with Roland on this. These paras on p14 justify his suggestion:
>>>    • Consider the behaviour of both trains during and following the
>>> collision and the
>>> damage caused to each
>>>    • Consider the actions taken on the day of the accident to manage
>>> the risk of low
>>> adhesion given the time of year and prevailing weather conditions
>>>    • Consider the actions of the driver of 1L53 and any factors which
>>> may have
>>> influenced them
>>>    • Consider South Western Railway's policies and processes relating
>>> to operating
>>> trains in conditions of low wheel/rail adhesion including the
>>> dissemination and
>>> responses to information
>>
>> I don't think there is anything in there out of the RAIB's norms. I
>> see nothing to support any reading between the the lines.
>
> See also:
>
> Train driving
> ===========
>
> 37 OTDR data shows that train 1L53 was travelling within the permitted
> speed as the train approached Salisbury Tunnel Junction. RAIB's
> investigation will continue to consider the driver's actions and factors
> that may have influenced them, including the industry's arrangements for
> advising drivers about poor adhesion conditions and the guidance and
> instructions relating to reporting low adhesion and driving in such
> conditions.

What's to read between the lines in that?

In message <sv2tdf$a5n$1@dont-email.me>, at 14:53:35 on Tue, 22 Feb
2022, martin.coffee@round-midnight.org.uk remarked:
>On 22/02/2022 14:29, Roland Perry wrote:
>> In message <sv2qam$iiq$1@dont-email.me>, at 14:00:54 on Tue, 22 Feb
>>2022, martin.coffee@round-midnight.org.uk remarked:
>>> On 22/02/2022 13:30, Recliner wrote:
>>>> On Tue, 22 Feb 2022 13:25:27 +0000,
>>>>martin.coffee@round-midnight.org.uk wrote:
>>>>
>>>>> On 22/02/2022 13:13, Roland Perry wrote:
>>>>>> In message <sv2m9u$lih$1@dont-email.me>, at 12:52:14 on Tue, 22 Feb
>>>>>> 2022, Certes <none@nowhere.net> remarked:
>>>>>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>>>>
>>>>>>>> The  one thing I noticed is that the circumstances are identical to
>>>>>>>> an  event in Sunningdale about 25 years ago.  The RHTT had not run
>>>>>>>> and a  train on the Chertsey branch slid onto the main line.
>>>>>>>> Fortunately no  other train was involved.
>>>>>>
>>>>>>>>   The rules should be change to be changed so that normal trains are
>>>>>>>> banned if the RHTT has not run within the prescribed time.
>>>>>>>
>>>>>>> Perhaps they could get away with asking drivers to travel below
>>>>>>> normal speed limit, as they do in extreme heat or other
>>>>>>>unhelpful weather conditions, and to be especially cautious
>>>>>>>approaching junctions even if it results in late running.
>>>>>>
>>>>>> Reading between the lines (sorry) I think they are not yet
>>>>>>convinced the driver was being sufficiently defensive, and are
>>>>>>looking at why that might be the case.
>>>>>
>>>>> What evidence do you have for that statement?

>>>>  I agree with Roland on this. These paras on p14 justify his suggestion:
>>>>    • Consider the behaviour of both trains during and following
>>>>the collision and the
>>>> damage caused to each
>>>>    • Consider the actions taken on the day of the accident to
>>>>manage the risk of low
>>>> adhesion given the time of year and prevailing weather conditions
>>>>    • Consider the actions of the driver of 1L53 and any factors
>>>>which may have
>>>> influenced them
>>>>    • Consider South Western Railway's policies and processes
>>>>relating to operating trains in conditions of low wheel/rail
>>>>adhesion including the dissemination and responses to information
>>>
>>> I don't think there is anything in there out of the RAIB's norms. I
>>>see nothing to support any reading between the the lines.

>> See also:
>> Train driving
>> ===========
>> 37 OTDR data shows that train 1L53 was travelling within the
>>permitted speed as the train approached Salisbury Tunnel Junction.
>>RAIB's investigation will continue to consider the driver's actions
>>and factors that may have influenced them, including the industry's
>>arrangements for advising drivers about poor adhesion conditions and
>>the guidance and instructions relating to reporting low adhesion and
>>driving in such conditions.
>
>What's to read between the lines in that?

OK, I was being polite about "reading between the lines", if you think
they were a bit more explicit than that.
--
Roland Perry

Roland Perry <roland@perry.co.uk> wrote:
> In message <gun91hhhpihfroc3fuvohjquqra44k38s7@4ax.com>, at 13:14:42 on
> Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>> On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:
>>
>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>> The  one thing I noticed is that the circumstances are identical to an
>>>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>>>> train on the Chertsey branch slid onto the main line.  Fortunately no
>>>> other train was involved.
>>>>
>>>> The rules should be change to be changed so that normal trains are
>>>> banned if the RHTT has not run within the prescribed time.
>>>
>>> Perhaps they could get away with asking drivers to travel below the
>>> normal speed limit, as they do in extreme heat or other unhelpful
>>> weather conditions, and to be especially cautious approaching junctions
>>> even if it results in late running.
>>
>> In this case, the train would have had to be travelling a *lot* slower
>> than normal to avoid the collision, let alone a
>> SPAD. With almost no friction, almost any speed could lead to a SPAD;
>> normal autumnal defensive driving wouldn't have
>> been enough.
>>
>> The SWR train was travelling at 86 mph at the start of braking, and
>> between 52 and 56 mph at the point of collision, more than a mile away.
>> To have been able to stop at the red signal, it would have had to be
>> cruising at less than 30 mph, rather than the usual 90 mph.
>
> It didn't need to stop *at* the red signal, rather than just soon enough
> not to foul the junction. [To avoid the accident, if not a SPAD report]
>

An extra 191m isn't going to make a lot of difference if the previous 1500m
didn't.

Anna Noyd-Dryver

In message <sv37eb$n6c$2@dont-email.me>, at 17:44:43 on Tue, 22 Feb
2022, Anna Noyd-Dryver <anna@noyd-dryver.com> remarked:
>Roland Perry <roland@perry.co.uk> wrote:
>> In message <gun91hhhpihfroc3fuvohjquqra44k38s7@4ax.com>, at 13:14:42 on
>> Tue, 22 Feb 2022, Recliner <recliner.usenet@gmail.com> remarked:
>>> On Tue, 22 Feb 2022 12:52:14 +0000, Certes <none@nowhere.net> wrote:
>>>
>>>> On 22/02/2022 10:59, martin.coffee@round-midnight.org.uk wrote:
>>>>> The  one thing I noticed is that the circumstances are identical to an
>>>>> event in Sunningdale about 25 years ago.  The RHTT had not run and a
>>>>> train on the Chertsey branch slid onto the main line.  Fortunately no
>>>>> other train was involved.
>>>>>
>>>>> The rules should be change to be changed so that normal trains are
>>>>> banned if the RHTT has not run within the prescribed time.
>>>>
>>>> Perhaps they could get away with asking drivers to travel below the
>>>> normal speed limit, as they do in extreme heat or other unhelpful
>>>> weather conditions, and to be especially cautious approaching junctions
>>>> even if it results in late running.
>>>
>>> In this case, the train would have had to be travelling a *lot* slower
>>> than normal to avoid the collision, let alone a
>>> SPAD. With almost no friction, almost any speed could lead to a SPAD;
>>> normal autumnal defensive driving wouldn't have
>>> been enough.
>>>
>>> The SWR train was travelling at 86 mph at the start of braking, and
>>> between 52 and 56 mph at the point of collision, more than a mile away.
>>> To have been able to stop at the red signal, it would have had to be
>>> cruising at less than 30 mph, rather than the usual 90 mph.
>>
>> It didn't need to stop *at* the red signal, rather than just soon enough
>> not to foul the junction. [To avoid the accident, if not a SPAD report]
>
>An extra 191m isn't going to make a lot of difference if the previous 1500m
>didn't.

It would if it's the difference between no fouling the junction, and
fouling it by 20m.

As for the dodgy physics above, 86^2 is 7400, and 54^2 is 2900.

So it had burnt off 4500, which means a defensive cruising speed of
67mph could have been slow enough (not 30mph!)
--
Roland Perry

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 22/02/2022 00:53, NY wrote:
build-up.
>>
>> Is wheelslide on braking a new phenomenon, or did it also exist with
>> loco-hauled trains (as opposed to multiple units) with their heavier
>> axle loads on the loco's driving/braked wheels. Did tyre brakes on steam
>> locos help to keep the tyres and hence the rails more clear of leaf
>> mulch? Did fewer trees on cuttings in the old days help a lot? Or has it
>> always been a problem?
>
> Yes, there were slipping problems in steam days, not just from leaves.
> Just look at videos of Bullied Pacifics trying to start a heavy train
> out of Waterloo!
> https://www.youtube.com/watch?v=iKzRNrDH5AU
> https://www.youtube.com/watch?v=jWNa2k0PSsM
>

The difference though is those were locomotives slipping because they were
moving a train from standstill, sand was applied to driving wheels to help
them get a grip.The sanding equipment could be employed on and off as
required until the hopper was empty.
Todays problem is the opposite with it being loss of braking with multiple
wheel sets sliding despite systems which are supposed to minimise it.
Hence the fitment to some stock of sanding equipment
designed to only be used in emergency circumstances ,the crudest works much
like the fire extinguishers it was developed from and once activated thats
it for the moment and it only gets applied from the front of the train in
front of the leading wheels ,following wheel sets are relying on some sand
still being in place on the railhead .

GH