Why do trains halt before carrying on to the platform?

[mailman]

Im on a roll today

But can someone explain why, when you watch a train approaching the platform that it will halt right at the start of the platform where the tunnel ends for a few seconds (or minutes) before then starting up again and carrying on to the platform?

Ive noticed trains doing this even when the platform hasnt had a train on it for long periods of time. Wouldnt it just make sense to get in to the platform to get people off and on to the train?

Just seems to me to be just another little thing that winds people up too, well, me at least

Regards

Mailman

 

[ainsworth74]

What station are we talking about here?

 

[Anon Mouse]

probably due to such a minor thing like signals

 

[mailman]

Ainsworth, mostly seen at Aldgate East but noticed at a number of other stations as well.

Anon Mouse,

That doesnt explain WHY the train would stop before carrying on to an empty platform, one that has been empty for long periods of time. WHY is the train being signalled to stop when the platform is empty?

Regards

Mailman

 

[Minilad]

Im confused !

 

[Wyvern]

Is there a train moving elsewhere on the station?

 

[trentside]

If you're talking about Aldgate East, that's the junction between the District and Hammersmith & City lines, so trains running on the eastbound District have to hold outside the platforms if a westbound H&C train is given priority over the junction towards Liverpool Street.

 

[tom1649]

I've only ever seen this happen when the platform has only just been vacated by the previous train.

 

[Greenback]

Just a thought, but is there some sort of automatic train control on the approach to stations, like on NR when a train approaches a terminus?

 

[DavyCrocket]

The points ahead of the station are probably locked with the home signal lever too, and thats is whats happening!

 

[Daniel]

Quite possibly a draw up signal. If the overlap on the station starting signal fouls point work you may see draw up signals.

Basically, if a train can go through the station starter, have the brakes applied, but still roll forward enough to foul a set of points, then that's unsafe. So, the safest thing to do is reduce the speed of the train.

You can do this by inserting another signal, and trainstop, and a timing section. This signal remains red, and waits for the train to enter the start of the timing section. The draw up signal will clear to a yellow* aspect when a set period of time has passed. The fact that the train hasn't reached the train stop before this time proves that the train is travelling slow enough to be stopped short of point work if tripped by the station starter.

*if the start was already clear, the draw up would be displaying a green aspect anyway, as it isn't protecting anything.

Again, it may be something to do with the specific area. Lets look at my area, Harrow-on-the-Hill.

The home signal, (the last signal before the platform), for platform 6, is JB64. It's right at the north end (of the southbound) platform. Platform 6 may not have had a train for over an hour. But if I've routed a train out of platform 5 across onto the fasts, via station starting signal JB51 I can't clear JB64 to get the next train into platform 6. Once the train in Platform 5 has passed JB51 and it has returned to danger I can normalise the signal lever for JB51, and reverse JB64 - however JB64 still will not clear, until the train which departed from PF5 has cleared the point work to the south of the platforms, and the points have returned to normal.

Everything is interlinked, it's all about having the safest method of working. There are oddities out there - for example I can cross a train from PF6 onto the slows but still bring a train up into PF5, but not the other way around. But oh well, we do what we can I suppose.

 

[DavyCrocket]

Just to add that a draw up signal does not have to have a green aspect.

But yes putting one in protects the points in advance. Otherwise as mentioned its a wait at the signal before. This happens a fair bit at Acton Town on the eastbound and at Earl's Court arriving into platform 2 amongst many others!

 

[mailman]

Daniel and Davey,

Thanks for the time you put in to your thorough explanations. It all makes sense now. I shall no longer stand on the platform tut tutting the trains for stopping before entering the station

Regards

Mailman

 

[Daniel]

Just to add that a draw up signal does not have to have a green aspect.

Ah yes - just for my own benefit, is that when the station starter is also approach controlled (ala Baker Street Met), or do we have locations of the network with a yellow followed by a green both cleared at the same time?

Daniel and Davey,

Thanks for the time you put in to your thorough explanations. It all makes sense now. I shall no longer stand on the platform tut tutting the trains for stopping before entering the station

Regards

Mailman

Ah, but you shall now also understand when a train draws in and gets tripped halfway down the platform because the driver was going too fast. His/her face will also turn a little red...

 

[mailman]

And as he passes me Ill make sure to waggle my "knowing" finger at him

Regards

Mailman

 

[A60K]

And as he passes me Ill make sure to waggle my "knowing" finger at him

You could do that, but generally if a driver has caused their train to be tripped they won't be feeling in the best of moods - if someone did waggle their finger me I would think ' what an ****'! Some might make a finger gesture back, and if reported to LU it could get them in a lot of trouble.

 

[Anon Mouse]

or some might say, I've dropped a clanger so I can't continuie my shift and your train will be cancelled!