Platforming Trains

[northernchris]

At major stations it obviously takes a lot of planning to ensure platforms are available for trains at their scheduled time. However when trains are running with longer formations than usual is there a system which detects this and a new platform is needed? Only reason I ask is I saw a train today which was put behind one due out 12 minutes after, so it left around 15 minutes late

 

[380101]

At major stations it obviously takes a lot of planning to ensure platforms are available for trains at their scheduled time. However when trains are running with longer formations than usual is there a system which detects this and a new platform is needed? Only reason I ask is I saw a train today which was put behind one due out 12 minutes after, so it left around 15 minutes late

Usually the TOC control will advise the relevant Signaller / Network Rail Control of the change in formation if a set has been increased in size. Failing that the Driver will know by his route knowledge whether his train will fit on the platform and on being routed into a short platform would stop at the signal and inform the signaller of his increased length and that he may not fit.

Also, certain platforms may not be able to accommodate certain formations of the same train. Platforms 12 and 13 at Glasgow Central are like this. If driving a 4 car 380 we cannot be called on to 12 or 13 if there is a 3 car 380 or 314 in already as the back coach will be hanging off. Had to call up the signaller a few times and then sit until he can get me into another platform.

 

[edwin_m]

Some termini have feature in the signalling known as Lime Street Control (no prizes for guessing where it was first used...). This has track circuits of particular lengths in the platforms and the approach tracks and will only clear the signal if there is enough room in the platform for the train routed into it.

 

[jamieP]

Some termini have feature in the signalling known as Lime Street Control (no prizes for guessing where it was first used...). This has track circuits of particular lengths in the platforms and the approach tracks and will only clear the signal if there is enough room in the platform for the train routed into it.

Obviously that cant stop a signaller routeing a train into the platform that is longer than the room left in the platform.

 

[edwin_m]

Obviously that cant stop a signaller routeing a train into the platform that is longer than the room left in the platform.

That is exactly what it is supposed to do. I don't see why it is obvious that it can't - you need to explain this post.

 

[PHILIPE]

Obviously that cant stop a signaller routeing a train into the platform that is longer than the room left in the platform.

As happened when 150219 ran into the back of an HST at Plymouth earlier this year but in this case there was no overlength train.

 

[jamieP]

That is exactly what it is supposed to do. I don't see why it is obvious that it can't - you need to explain this post.

Kings Cross for example mainline platforms, can have a single 180 down on the stops with room for an 8 car unit to arrive on top. Lime Street control will allow the signal to clear as there is room but would still clear even if the train arriving on top of the 180 happened to be a 12 car unit even tho its over length.

 

[snowball]

Where does Lime Street control get its knowledge of the lengths of approsching trains?

 

[Tomnick]

Where does Lime Street control get its knowledge of the lengths of approsching trains?

Track circuits laid out in such a way that they can 'measure' trains approaching the last signal before the station. It's pretty inflexible - i.e. if it's laid out for four-car units (multiples of four), a three-car unit standing against the buffer stops might prevent a nine-car set being signalled in on top. Defensive driving policies might cause a problem too - trains stopping further away from the signal than the design allowed for?

 

[dgl]

Where does Lime Street control get its knowledge of the lengths of approsching trains?

Track circuits, I would guess that there are lengths of track on approach to the station split into different track circuits with each length of track circuit being a certain train length and insulated from the next section, the more circuits the train occupies when it stops in the measuring section the longer it is and that is relayed to the signalling system and by knowing the length of the platform, if any trains are already in it and from the track circuit the approximate length of the train or knows whether or not out van release the signal and allow it into the platform.

 

[Sunset route]

Copy of the relevant page.

 

[edwin_m]

Kings Cross for example mainline platforms, can have a single 180 down on the stops with room for an 8 car unit to arrive on top. Lime Street control will allow the signal to clear as there is room but would still clear even if the train arriving on top of the 180 happened to be a 12 car unit even tho its over length.

Lime Street control would only allow the signals to clear if the approaching train was shorter than the space available. So it obviously isn't applied to these platforms, at least not for this specific combination of trains. From other posts it's clear that it would get very complicated to provide for every combination at a station where there are many different train lengths.

 

[JN114]

I should point out that Lime St controls aren't provided everywhere. At many, many locations where platform sharing takes place the reliance is on the signalman/driver knowing what will and will not fit. Signalmen have access to TRUST, which generally provides consist information.

 

[The Planner]

Many stations will also have simplifiers either written by themselves or provided by us.

 

[Crossover]

Some termini have feature in the signalling known as Lime Street Control (no prizes for guessing where it was first used...). This has track circuits of particular lengths in the platforms and the approach tracks and will only clear the signal if there is enough room in the platform for the train routed into it.

Not sure if it is an example of Lime Street Control, but Huddersfield p4 has a restriction on train length (2 car platform only - even a 3 car 144 won't fit from what I recall) - I understand the approach signal remains red until the train is proved as being of suitable length to fit. This makes for quite a slow approach to this platform as the restrictions means the train does usually have to stop at the signal before it will clear for p4

 

[RichardN]

Both trains and staff can effect the operation of the terminals too...

I heard an announcement on a (delayed) approach to London Bridge from the guard that the driver had been informed by the signaller that we were waiting for (a service to depart platform X - exact details lost in my memory). The guard's next sentence was "I've just told the driver he might have a long wait as I'm booked as the guard on that service."

 

[edwin_m]

Not sure if it is an example of Lime Street Control, but Huddersfield p4 has a restriction on train length (2 car platform only - even a 3 car 144 won't fit from what I recall) - I understand the approach signal remains red until the train is proved as being of suitable length to fit. This makes for quite a slow approach to this platform as the restrictions means the train does usually have to stop at the signal before it will clear for p4

Sounds like Lime Street Control. However there are often approach controls on routes into short bay platforms, to slow an approaching train more in case the driver believes he has an empty full-length platform to stop in. These wouldn't necessarily check the train length, but the approach would be just as slow and 99.9% of the time it would be impossible to tell.