Train running information. How does it work?

[mafeu]

mods note - split from here.

I’ve noticed that the indication to the signalling system that a train has arrived/departed can be quite a stretch down the line.

So how do we define the arrival time for Delay Repay? Is it when the signal is triggered or when the train is at platform and the doors are released? I’d say the later is more appropriate.

I know we’ve taken back control () but I see this EU flight compensation case as having relevance even if it is related to aviation.Link

 

[PZ 08895]

I’ve noticed that the indication to the signalling system that a train has arrived/departed can be quite a stretch down the line.

So how do we define the arrival time for Delay Repay? Is it when the signal is triggered or when the train is at platform and the doors are released? I’d say the later is more appropriate.

I know we’ve taken back control () but I see this EU flight compensation case as having relevance even if it is related to aviation.Link

Yes you are quite correct that in many cases the signal positions do not directly relate to a platform location.

Tain running information is initially reported by systems called train describers (TDs) which generally report on the movement of trains by a step from one signal berth (section) to another using information from either track circuits or axel counters. A typical message will say that train NXNN as stepped from nnnn signal berth to nnnn signal berth.

However these TD berth steps rarely totally correspond to a timing point. For example, at a terminal station the last signal will usually be passed a significant tine before the train comes to a stop. Similarly when the train departs from a terminal station there will be a significant time difference between the train starting to move and the platform starter signal being passed, especially for a short train.

To overcome this issue, either positive (additional time) or negative (time removed) offsets are applied to the berth-step information so as to be as accurate as possible on the time of the actual event, such as a train arriving or departing from a station.

Whilst every effort is made to make these offsets as accurate as possible, obviously it cannot he totally exact as train performance and length on a line can vary depending on the train type as well as other factors such as if a train has been slowed by signals and is therefore travelling slower than normal the time reported at a timing point maybe slightly too early or late.