GWML Electification

[Grovenor]

That problem will arise when drivers don't follow the meaning of the subsidiary aspect, adding in variant meanings of that aspect when there are marker boards is just adding to the confusion and making mistakes more likely.

Regards

[Coryton]

That problem will arise when drivers don't follow the meaning of the subsidiary aspect, adding in variant meanings of that aspect when there are marker boards is just adding to the confusion and making mistakes more likely.

Regards

 

I suppose that depends on what the rules are.

 

I was assuming that calling-on to a marker board had the same meaning as normal, i.e. drive on line of sight, in which case I don't see a problem. If the driver forgets they are supposed to be stopping at the big cross rather than another train no real harm has been done.

 

I agree that if the meaning in Bristol is actually to treat it as a yellow aspect with the cross being the red signal then yes, I can see plenty of scope for confusion.

 

Alhough I'm not sure that the Bristol system does use calling on.

 

The page here https://www.railengineer.uk/2016/10/26/bristol-area-signalling-renewals/

seems to be saying that the same aspect is given for both ends of a platform with the only difference being the platform number displayed on the signal.

[Great Western]

Can I assume you are not a fan?

You can Sir.

[96701]

As Temple Meads hasn't complied with normal standards ever since it was resignalled over 40 years ago, and as Reading could be said also to not comply (because it is effectively signalled in exactly the same way as Temple Meads was 40+ years ago) I can't really see what the problem is beyond 'obstructionism' from those of very limited brain power and considerable lack of experience.

 

For those not familiar with either station - in both cases the platforms are artificially divided into two sections by marker/stop marker boards and an approaching train receives either a main aspect to indicate the platform is clear to the signal at the far end or it receives a sub indication which indicates that a train may only proceed as far as the relevant stop marker.  in many respects the latter is very similar to running in on a subsidiary to an occupied platforms but in the case of both Bristol and Reading there is a physical mark to limit the extent of the movement authorised by the subsidiary.  I am certain that a quantitive risk assessment - which has masses of real data to draw on - would indicate that this method of working has relatively little potential for collisions even when compared with a similar assessment of locations where no marker is provided.

 

The modern NR railway really needs to grow a pair.

Cardiff Central seems to manage permissive working on many platforms on many occasions every day. In this instance, NR has a pair of fully grown.

[Great Western]

As Temple Meads hasn't complied with normal standards ever since it was resignalled over 40 years ago, and as Reading could be said also to not comply (because it is effectively signalled in exactly the same way as Temple Meads was 40+ years ago) I can't really see what the problem is beyond 'obstructionism' from those of very limited brain power and considerable lack of experience.

 

For those not familiar with either station - in both cases the platforms are artificially divided into two sections by marker/stop marker boards and an approaching train receives either a main aspect to indicate the platform is clear to the signal at the far end or it receives a sub indication which indicates that a train may only proceed as far as the relevant stop marker.  in many respects the latter is very similar to running in on a subsidiary to an occupied platforms but in the case of both Bristol and Reading there is a physical mark to limit the extent of the movement authorised by the subsidiary.  I am certain that a quantitive risk assessment - which has masses of real data to draw on - would indicate that this method of working has relatively little potential for collisions even when compared with a similar assessment of locations where no marker is provided.

 

The modern NR railway really needs to grow a pair.

 

As most will be aware the even station curves to the left if looking from the East Gantry, there was an issue with trains coming in on the dots (so onto a odd numbered platform) with a train already in there. This was especially bad on platform 5, drivers were instructed to proceed at a speed which they could stop short of obstruction which some drivers took to be 5mph.

 

The problem was real, its a real butt tingling moment when you round into platform 5 and see a 158 way back from the cross staring at you!

[Great Western]

Cardiff Central seems to manage permissive working on many platforms on many occasions every day. In this instance, NR has a pair of fully grown.

 

I know before the resignalling the chargeman would issue movement authority to the driver upon arrival of the inbound working.

 

For example a terminating service would arrive in on platform 3, the chargeman would say that once you've been down the Brickyard and come back into platform 2 proceed down as far as clear or proceed only to the train prep board, and await a handsignal to draw forward.

 

Easy, clear and understood.

[DY444]

As most will be aware the even station curves to the left if looking from the East Gantry, there was an issue with trains coming in on the dots (so onto a odd numbered platform) with a train already in there. This was especially bad on platform 5, drivers were instructed to proceed at a speed which they could stop short of obstruction which some drivers took to be 5mph.

 

The problem was real, its a real butt tingling moment when you round into platform 5 and see a 158 way back from the cross staring at you!

 

Interesting that there was felt to be a need to issue an instruction.  I believe the rulebook is clear that drivers should be prepared to stop short of an obstruction when proceeding under dots and must therefore regulate their speed accordingly.  This also featured in the Plymouth collision and so I wonder if there might be a driver training issue here because it sounds like some drivers were unaware of the precise meaning of the dots.

Edited February 27, 2018 by DY444

[Coryton]

I know before the resignalling the chargeman would issue movement authority to the driver upon arrival of the inbound working.

 

For example a terminating service would arrive in on platform 3, the chargeman would say that once you've been down the Brickyard and come back into platform 2 proceed down as far as clear or proceed only to the train prep board, and await a handsignal to draw forward.

 

Easy, clear and understood.

 

That works for trains that start in Cardiff, but I've seen arriving trains come in behind other ones so unless they were stopped at the previous signal to phone the signaller, I don't think they could have been given verbal instructions.

 

(This is apparently why trains arriving on 3 and 4 have to draw up to the far end of the platform making everybody walk back to the subway - so that there's plenty of space for another train to come in behind if necessary).

[Edwin_m]

Nottingham has a similar system to Cardiff, with no mid-platform signals but some small signs saying "Berth A", B or C.  I believe the instruction is for short trains to pull up in berth B unless otherwise hand-signalled by the platform staff, thus leaving enough room (in the long platforms) for another short train to arrive from either end. 

[The Stationmaster]

What I assume the marker boards to be at Reading are white circles with a black triangle on it.

 

How that kind of thing can be outside standards is absolutely staggering. Working trains into occupied platforms is not exactly going to go away, and is in fact crucial to the operation of the railway.

 

Obviously, as Simon has mentioned, either some sort of derogation was applied at reading or it is compliant with particular standard.  Whichever is the case the logical conclusion is that if it could be done at Reading then it could be done elsewhere should similar circumstances prevail.  Bristol TM has an AWS 'gap' through the station, Reading does not;  Bristol TM lies on a curve with potentially awkward siting, Reading arguably has better siting of the boards and it is definitely far easier (except on one platform) for a Driver to easily reference their position; Reading also has 'closing-up' signals at the approach to some platforms which reduces the distance run on a sub aspect (albeit at the expense of short signal sections and restrictive speeds due to reduced braking distances).  and of course, as noted above, at temple meads it is the platform number in the route indicator which gives the Driver the limit of movement.

 

As i said - all it needs is some careful thought about how the job could be done supported by risk assessment if there is any doubt.  With any signalling scheme there is often more than one way of skinning a particular cat and if a signal engineer, in conjunction with the operators, has to apply some original thought (as was done at Temple Meads when it was last resignalled) then so be it.

[Pandora]

That works for trains that start in Cardiff, but I've seen arriving trains come in behind other ones so unless they were stopped at the previous signal to phone the signaller, I don't think they could have been given verbal instructions.

 

(This is apparently why trains arriving on 3 and 4 have to draw up to the far end of the platform making everybody walk back to the subway - so that there's plenty of space for another train to come in behind if necessary).

Thee platform line will be divided up into several consecutive track circuits which "belong to" the entry signal,  the working method  you describe is known as permissive,  the train has to pull up to the buffer stops to vacate suffficent  track circuits to allow the entry signal to show a proceed  aspect, the signal interlocking logic will therefore restrict the  proceed aspect to show DANGER  plus the subsidiary aspect of two dots or white lights, meaning to the Driver, proceed at caution at far as you can see is clear.

if the train did not pull up to the stops and occupy too many track circuits, the signal would remain at DANGER and no more

[Coryton]

Thee platform line will be divided up into several consecutive track circuits which "belong to" the entry signal,  the working method  you describe is known as permissive,  the train has to pull up to the buffer stops to vacate suffficent  track circuits to allow the entry signal to show a proceed  aspect, the signal interlocking logic will therefore restrict the  proceed aspect to show DANGER  plus the subsidiary aspect of two dots or white lights, meaning to the Driver, proceed at caution at far as you can see is clear.

if the train did not pull up to the stops and occupy too many track circuits, the signal would remain at DANGER and no more

 

Quite.

 

I was responding to what seemed to be a suggestion that in Cardiff, permissive working included verbal instructions as well as a calling-on signal - which may be the case when trains move from an arrival to a departure platform, but I don't think is the case otherwise.

[DavidB]

But in reality most of the distance between Milton and Uffington (exclusive) is not only wired butt has been wired for some time.  

Apologies if it's already been noted and I've missed it, but 800s have started running on the UM through Didcot non-stop with pantographs raised.  Does this mean that the wires are now live west of Didcot (even if not very far, due to the small issue of Steventon)?

[royaloak]

As Temple Meads hasn't complied with normal standards ever since it was resignalled over 40 years ago, and as Reading could be said also to not comply (because it is effectively signalled in exactly the same way as Temple Meads was 40+ years ago) I can't really see what the problem is beyond 'obstructionism' from those of very limited brain power and considerable lack of experience.

 

For those not familiar with either station - in both cases the platforms are artificially divided into two sections by marker/stop marker boards and an approaching train receives either a main aspect to indicate the platform is clear to the signal at the far end or it receives a sub indication which indicates that a train may only proceed as far as the relevant stop marker. in many respects the latter is very similar to running in on a subsidiary to an occupied platforms but in the case of both Bristol and Reading there is a physical mark to limit the extent of the movement authorised by the subsidiary. I am certain that a quantitive risk assessment - which has masses of real data to draw on - would indicate that this method of working has relatively little potential for collisions even when compared with a similar assessment of locations where no marker is provided.

 

The modern NR railway really needs to grow a pair.

Reading platforms are not split into two, they simply have markers to indicate when they are in clear.

 

As for your 'obstructionism' comment, you really can't help yourself can you!

 

What we have at BRISTOL might not be compliant but we are all aware of what is involved, the new method is just plain stupid, getting a single yellow with an 8 when you need to get to platform 9 so your train is accommodated for example, but we are expected to accept that, stop on platform 8 (with the back end off the platform) and then when the position light clears to move up and attach without anyone checking the PTI is clear. Now anyone with half a brain can see the problems there, but in your world I suppose that is just me being 'obstructive' isn't it!

 

It might prevent collisions (my eyes do the same thing) but they do not take into account the passenger's and having to stop in one platform before moving onto the second one is a recipe for disaster, but then it won't be you or the one who carried out the risk assessment in Court will it when somebody falls down the gap and has their legs chopped off because the train stopped and then started moving again will it.

 

Edited due to sarcastic comment from the usual suspect.

Edited March 1, 2018 by royaloak

[The Stationmaster]

Apologies if it's already been noted and I've missed it, but 800s have started running on the UM through Didcot non-stop with pantographs raised.  Does this mean that the wires are now live west of Didcot (even if not very far, due to the small issue of Steventon)?

 

The wires have been live as far as Milton since the original commissioning David so presumably the Instructions have been amended to allow pans on non-stop trains to be raised in the vicinity of Foxhall Jcn or thereabouts?

[The Stationmaster]

Reading platforms are not split into two, they simply have markers to indicate when they are in clear.

 

As for your 'obstructionism' comment, you really can't help yourself can you!

 

What we have at BRISTOL might not be compliant but we are all aware of what is involved, the new method is just plain stupid, getting a single yellow with an 8 when you need to get to platform 9 so your train is accommodated for example, but we are expected to accept that, stop on platform 8 (with the back end off the platform) and then when the dummy clears to move up and attach without anyone checking the PTI is clear. Now anyone with half a brain can see the problems there, but in your world I suppose that is just me being 'obstructive' isn't it!

 

It might prevent collisions (my eyes do the same thing) but they do not take into account the passenger's and having to stop in one platform before moving onto the second one is a recipe for disaster, but then it won't be you or the one who carried out the risk assessment in Court will it when somebody falls down the gap and has their legs chopped off because the train stopped and then started moving again will it.

You really ought to read what I wrote and not what you think I wrote as I was writing about the original signalling into the platform.  You appear to think I was criticising you although I can't think why  .  Interesting to hear that dummies have been added mid platform at Temple Meads - presumably an idea to save platform staff?

 

And if Reading platforms aren't split into two why do they have two separate numbers and why can they accommodate two separate trains doing two different things?

[phil-b259]

Reading platforms are not split into two, they simply have markers to indicate when they are in clear.

 

As for your 'obstructionism' comment, you really can't help yourself can you!

 

What we have at BRISTOL might not be compliant but we are all aware of what is involved, the new method is just plain stupid, getting a single yellow with an 8 when you need to get to platform 9 so your train is accommodated for example, but we are expected to accept that, stop on platform 8 (with the back end off the platform) and then when the dummy clears to move up and attach without anyone checking the PTI is clear. Now anyone with half a brain can see the problems there, but in your world I suppose that is just me being 'obstructive' isn't it!

 

It might prevent collisions (my eyes do the same thing) but they do not take into account the passenger's and having to stop in one platform before moving onto the second one is a recipe for disaster, but then it won't be you or the one who carried out the risk assessment in Court will it when somebody falls down the gap and has their legs chopped off because the train stopped and then started moving again will it.

 

Why would you have to 'wait for the dummy to clear'?

 

Granted it is usual to make trains come to a stand at a signal before allowing the sub signal to clear but that does not mean that Bristol has to slavishly follow that principle - which can in any case be defeated sometimes by creping very slowly towards the sub signal.

 

Consider for a moment the situation where you are entering a platform on a single yellow having received a single yellow aspect, but the platform is a terminus with a buffer stop at the end. TPWS will ensure that you are doing no more 10mph (IIRC) with the consequence that it takes quite a lot of time between starting to enter the platform and getting to the stage you need to brake to a stand as you get close to the buffers.

 

So, if the new Bristol signalling (i) enforces a sufficiently low platform entry speed, and (ii) The track circuit occupancy timers used to determine how long the berth track circuit (the one running up to the signal for non railway folk) has been occupied are set correctly, it should be possible to get the sub signal to show a proceed as you are approaching it.

 

Tue if you pass the yellow aspect and continue at 'normal' speed then you might well be too quick and end up having to come to a stand - but as with the old fable of the Hare and the Tortoise, sometimes things are not always what they may seem.

Edited March 1, 2018 by phil-b259

[royaloak]

BRI is going to be set up so you are always brought to a stand before the position light signal (best not call it a dummy) clears no matter how slow you approach it.

[phil-b259]

BRI is going to be set up so you are always brought to a stand before the position light signal (best not call it a dummy) clears no matter how slow you approach it.

 

Interesting, as unless they have some sort of treadle setup that has to be triggered I don't see how you can do it.

 

Track circuits or axle counter sections must not be shorter than the length of the longest vehicle - which in this case is the 26m IET (though the exact distance between the bogies is the same as a MK3) - hence the use of timers to delay signal clearance.

[St. Simon]

The wires have been live as far as Milton since the original commissioning David so presumably the Instructions have been amended to allow pans on non-stop trains to be raised in the vicinity of Foxhall Jcn or thereabouts?

Nope, the wires between the Swindon end of Didcot Parkway and Milton Junction are live, but NOT signed in to use for passenger units, the instruction remains that Non-Stop Trains must wait until the Safe Pan Raising Area at South Moreton unless they get checked to below 20mph (as per rule book) with Stopping Trains having the option to Change-over whilst stationary in the platform (although this is still against my safety case).

 

Simon

[jim.snowdon]

I'm a bit surprised that raising the pantographs with the train stationary in the platform should be a safety case issue, given the extent to which it already happens at Farringdon and Ashford, to name but two.

 

Jim

[Peter Kazmierczak]

Agree with Jim; happens every few minutes at Drayton Park on the Moorgate branch too..

 

Wonder if it's to do with Didcot having two different types of unit putting up their pans, whereas Farringdon et al is just the one type. Dunno really..........

[Peter Kazmierczak]

Just thought - could Didcot be in a more exposed location and suffer from cross-winds which might alter the dynamics of pan / OHLE interface?

[locoholic]

Just thought - could Didcot be in a more exposed location and suffer from cross-winds which might alter the dynamics of pan / OHLE interface?

No, it's because there's a danger of the sparks frightening the horses that will be used to haul the trains through the dead section at Steventon.

[The Stationmaster]

Interesting, as unless they have some sort of treadle setup that has to be triggered I don't see how you can do it.

 

Track circuits or axle counter sections must not be shorter than the length of the longest vehicle - which in this case is the 26m IET (though the exact distance between the bogies is the same as a MK3) - hence the use of timers to delay signal clearance.

 

It could still be done, albeit not necessarily an elegant engineering solution, with measuring track circuits but that would be more complicated.   Is the existing sub aspect approach released I wonder - I would have thought that it would be?