Performing shunts using ground position signals

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pompeyfan

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A question regarding an oddity of railway operations...

why is it that some shunts using ground position signals are permitted in passenger service, and yet others are not and the train must be de-trained before a reverse movement can take place?
 
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DoubleO

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Happy to stand corrected but I don't think any moves on position lights are permitted with a passenger service unless in an emergency and/or given special permission.
 

pompeyfan

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There is a shunt move that seems to permit it near St Denys, I would assume it’s potentially a special exemption under the sectional appendix or similar?
 

DoubleO

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Quite possibly. I've made moves on a PL with a pass service before, but only due to a points failure or similar issue, and then I've gained explicit authorisation from the signaller, control, and an on call manager.....

Is the train actually in service at the time of the move? I.e. can and does have passengers on board?
 

Tomnick

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Generally, shunt routes aren’t signalled to the standard required for passenger trains, e.g. adequate overlap and facing points locked etc., so additional measures might need to be taken in the box or on the ground before authority for a passenger train to be signalled over a shunt route can be granted.
 

pompeyfan

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Quite possibly. I've made moves on a PL with a pass service before, but only due to a points failure or similar issue, and then I've gained explicit authorisation from the signaller, control, and an on call manager.....

Is the train actually in service at the time of the move? I.e. can and does have passengers on board?

the move I refer to is a contingency based move. It is not used as a one off to free a trapped train but is used as a diversion route for a service group with passengers on board the train the entire time.
 

DoubleO

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I would imagine then that either there's a local instruction permitting the move, or it's deemed important enough to be authorised when required.
 

DennisM

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the move I refer to is a contingency based move. It is not used as a one off to free a trapped train but is used as a diversion route for a service group with passengers on board the train the entire time.

I’ve previously wondered the same, I believe the answer may be that it’s allowed when authorised in the WON.

Theres a couple of other examples I can think of on the SWR network where passenger services use ground position signals;
At Richmond (when lines through twickenham closed) services terminating in the down platform and starting back towards London on authority of GPS.
At Virginia Water (reading services diverted via weybridge) trains call at the station, perform a shunt behind a GPS at the London end and then call at the station again in a different platform before continuing their journey.
 

Mag_seven

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Happy to stand corrected but I don't think any moves on position lights are permitted with a passenger service unless in an emergency and/or given special permission.

But what about their use during platform sharing?

Edit: just realised we are of course talking about ground position signals specifically not subsidiary signals or "calling on" signals in general
 
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zwk500

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But what about their use during platform sharing?
That's permissive signals, not shunt signals. It's a Calling on or Warner route, not a Shunt route, therefore it will be fitted with facing point locks and the overlap for the signal with the permissive aspect will be sufficient to protect the occupied section (in combination with AWS/TPWS/Approach control).

With regards the OP's question, if the route has facing point locks (almost all electronically operated points have facing point locks by default), then the Operations Manager can write an instruction to permit their use. These can be one-off, issued direct to the Signal Box or in the Sectional Appendix. If there's a conflicting overlap then the instruction will include keeping the signal in rear at danger (double-red). Obviously, if that signal is not controlled by the box then the instruction cannot be issued (or you would need a handsignaller to key the signal back to danger for every move). This would be why some locations allow the practice and others do not.
 

swt_passenger

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I’ve previously wondered the same, I believe the answer may be that it’s allowed when authorised in the WON.

Theres a couple of other examples I can think of on the SWR network where passenger services use ground position signals;
At Richmond (when lines through twickenham closed) services terminating in the down platform and starting back towards London on authority of GPS.
At Virginia Water (reading services diverted via weybridge) trains call at the station, perform a shunt behind a GPS at the London end and then call at the station again in a different platform before continuing their journey.
Fareham P3 when used as a terminus from the Eastleigh direction. A few years back they always put a hand signaller with a yellow flag in place to authorise departures, and then not that long ago he wasn’t needed anymore.
There is a shunt move that seems to permit it near St Denys, I would assume it’s potentially a special exemption under the sectional appendix or similar?
I did that move regularly when the Botley line had the bad land slip a few years back. I suppose when it’s needed 24/7 for a couple of months there’s a good reason to have a local rule in place...
 

pompeyfan

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That's permissive signals, not shunt signals. It's a Calling on or Warner route, not a Shunt route, therefore it will be fitted with facing point locks and the overlap for the signal with the permissive aspect will be sufficient to protect the occupied section (in combination with AWS/TPWS/Approach control).

With regards the OP's question, if the route has facing point locks (almost all electronically operated points have facing point locks by default), then the Operations Manager can write an instruction to permit their use. These can be one-off, issued direct to the Signal Box or in the Sectional Appendix. If there's a conflicting overlap then the instruction will include keeping the signal in rear at danger (double-red). Obviously, if that signal is not controlled by the box then the instruction cannot be issued (or you would need a handsignaller to key the signal back to danger for every move). This would be why some locations allow the practice and others do not.

thats really helpful, thank you!
 

zwk500

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thats really helpful, thank you!
Depending on locations, there will be any number of variations and local considerations as part of the instructions. It's increasingly being phased out as newer standards mean you don't really save any money, and the shunt takes up time and may need a 2nd member of staff or stop boards to be laid out in advance.
 

pompeyfan

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Depending on locations, there will be any number of variations and local considerations as part of the instructions. It's increasingly being phased out as newer standards mean you don't really save any money, and the shunt takes up time and may need a 2nd member of staff or stop boards to be laid out in advance.

in order to maintain flexibility, if necessary I assume they are replacing shunt signals with main aspects?
 

RichardKing

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There used to be GPLs at the Eastbourne end of platforms 2 and 4 at Lewes, which signalled a fair few passenger trains that couldn't proceed north towards London/west towards Brighton respectively. As of a couple of years ago, these are no longer in use.
 

MadMac

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They used to depart the Cowdenbeath terminators back towards Edinburgh on a shunt - there was a local instruction permitting it.
 

zwk500

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There used to be GPLs at the Eastbourne end of platforms 2 and 4 at Lewes, which signalled a fair few passenger trains that couldn't proceed north towards London/west towards Brighton respectively. As of a couple of years ago, these are no longer in use.
Those signals have been replaced with main aspect signals, as has the GPL east of the junction, so that Plumpton <> Falmer reversals are carried out under full signalling. They've also added a fixed Stop signal on the Up line to allow reversals on both lines instead of just the Down. The only remaining GPL on a running line at Lewes is on the Up East Branch (Brighton), for shunting between 4 & 5.
 

Dunnyrail

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I think a Station somewhere between Newcastle and Berwick may do this due to there only being one platform?
 

zwk500

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I think a Station somewhere between Newcastle and Berwick may do this due to there only being one platform?
None that I'm aware of - Trains terminating at Morpeth shunt empty, and this section of the ECML is signalled for Bi-Di running so there's main aspects for both directions off either platform.
 

Bigman

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What about sleepers? Years ago I got a sleeper from Euston to Carlisle. The Carlisle sleeper car was shunted off the front of then train with an 08 shunter and then shoved into one of the Northern facing bays.
 

RichardKing

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Those signals have been replaced with main aspect signals, as has the GPL east of the junction, so that Plumpton <> Falmer reversals are carried out under full signalling. They've also added a fixed Stop signal on the Up line to allow reversals on both lines instead of just the Down. The only remaining GPL on a running line at Lewes is on the Up East Branch (Brighton), for shunting between 4 & 5.
Yeah, they did a good job of upgrading Lewes. And now I believe that terminating services from Brighton can arrive on platform 4 as a result of the upgrade? Handy if 5 is out of use.
 

TEW

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Another example on SWR in use today. Trains from Waterloo are terminating at Haslemere, and because 3tph are doing so they can't all use Platform 2 to turnaround. So 1tph is using Platform 1, which requires starting back off a ground position light towards Waterloo. It's another one done relatively often, usually in Platform 3 is out of use at Haslemere.
 

Surreytraveller

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Happy to stand corrected but I don't think any moves on position lights are permitted with a passenger service unless in an emergency and/or given special permission.
Leatherhead Down to Up. Oxted Up to Down. Purley Platform 2 to Up Fast
 

dk1

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It sounds like you are confusing the use of ground position signals. If say for example they are within a station they are used to assist with shunts but the passenger service will have been given permission initially through the main aspect or position light associated with that signal if proceeding into an occupied platform where permissive working is permitted.

If however the position light is for example to provide a wrong direction shunt move over a crossover which is not a normally signalled route, this could well be because the crossover is not provided with a point lock or the route it takes you to into sidings are also not provided with this & there are possibly hand points which unless clipped, are not cleared for passenger operation.
 

pompeyfan

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It sounds like you are confusing the use of ground position signals. If say for example they are within a station they are used to assist with shunts but the passenger service will have been given permission initially through the main aspect or position light associated with that signal if proceeding into an occupied platform where permissive working is permitted.

If however the position light is for example to provide a wrong direction shunt move over a crossover which is not a normally signalled route, this could well be because the crossover is not provided with a point lock or the route it takes you to into sidings are also not provided with this & there are possibly hand points which unless clipped, are not cleared for passenger operation.

Would like to think I have a pretty good understanding of the railway and how it works but there is always room for improvement. On this occasion though I don’t think I’m confused.

on the Open train times maps between Worting junction and Hinton Admiral at St Denys (just country side of the station) there is a GPS in the up direction on the down slow, there is also a LOS board in the down direction on the up fast. Both of these have been used recently to allow passenger trains to shunt for about 12 hours periods in both directions. By the sounds of it this signalling is to mainline standards which allows these to be used.

there is a further example at Virginia Water on the up line allowing passenger trains from Ascot towards London to shunt to gain access towards weybridge to allow the train to continue towards Waterloo.

As a general rule though it appears passenger trains using stand alone shunt signals that are not part of permissive working is not permitted.
 
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