How does train priorities work?

[TSR :D]

Not sure where to put this but anyway.

Let's say, there was 2 trains, and three stations. Let's label stations A B C in same order.

If a train from A going to C is running late, by about 15 minutes late which puts scheduled time arrival of 22:45 instead of 22:30. Then there's a stopping service train from B going to C (And 2 or so stations between it), and has scheduled time arrival of 22:45 as well.

Somewhere between BC, one station has extra platform.

Will BC train go to 'different' platform and sit wait while another train passes? Or it will just continue as normal? Those trains cannot arrive at C at same time as there is not enough platform and track is single.

Is it worth it if BC train sits in 'different' platform which will cause 10 minutes (Due to very tight time slots in train station) delay to its service for sake of another train that is already 15 minutes late

Bearing that both train is of different TOCs.

 

[The Planner]

I'm not sure how station C works if you say it is single and not enough platform space unless there is a siding somewhere for a train to shunt out to or it has left on the return journey.

You will probably find that as the train from A to C is 15 late and a PPM failure and the train from B to C is on time, holding the stopper is likely to cause two PPM failures, therefore the stopping service will probably go first.

 

[Aictos]

I'm not sure how station C works if you say it is single and not enough platform space unless there is a siding somewhere for a train to shunt out to or it has left on the return journey.

You will probably find that as the train from A to C is 15 late and a PPM failure and the train from B to C is on time, holding the stopper is likely to cause two PPM failures, therefore the stopping service will probably go first.

I like your example but from past experience that isn't always the case on the Great Northern,

 

[Techniquest]

Isn't it generally best to aim for the least late-running trains, thus the best possible PPM score? Granted, that doesn't always work in practice and examples could be drafted in from pretty much every corner of the UK rail empire, and reasons for such things are various.

The easiest way to look at it is this: What's better to have, one late train or two late trains? Answer? Neither, no late trains But no, one late train is obviously better than two.

 

[O L Leigh]

There are no predetermined priorities. It seems to depend on the interaction between Nitwit Rail and TOC controller.

To illustrate:

I was late coming up slow from Cambridge one evening ages ago. It was a wet night and I was about 5 late leaving because I was held up to wait for an FCC GN service to pass. I then lost another 10 minutes due to poor railhead conditions between Cambridge and Stansted South Junction. After that point the frequency of services meant that the railhead conditions improved and I lost no more time. However, the signaller put my in the back platform at Harlow Town to let a StanEx past and then, to add insult to injury, he also let out a service coming up from Hertford East in front of me. Result? I was MASSIVELY late into Liv St and so departed back down to Cambridge with such a heavy time penalty that by Whittleford Parkway the next service down to Cambridge was showing on the PIS screens as being only 3 minutes behind me.

A couple of weeks later I'm on the StanEx and following a badly delayed Cambridge service up to Liv St. Not to worry, thinks I. The signaller will put him behind somewhere and let me by, just as he did to me a couple of weeks before. Did he put him in at Bishops Stortford? No. Did he put him in at Harlow Town? No. Did he even put him in at Broxbourne? Not on your nelly. Bum cakes!!! Yup, I had to follow him the whole way up to Liv St while getting later and later.

O L Leigh

 

[Pumbaa]

As far as I'm aware, the general policy nowadays is for the box to signal trains through in the timetabled order, and let the TOCs squabble over the delay attribution. As soon as NR intervene and try and restore the service by 'sensible signalling', they get chinged for delaying trains. Madness.

I'm sure some of the resident siggies on here will be along soon to lambast!

 

[O L Leigh]

No. There are definate "slots" that you can miss if things get delayed, especially across junctions. If you're delayed by more than a certain amount there is a very good chance that the stopper you're meant to run ahead of will have already been signalled through ahead of you. This suggests that, at certain locations at least, there is a policy with regard to the signalling of late running trains.

O L Leigh

 

[Pumbaa]

Of course, I was attempting to suggest that in a basic model where a signaller has control of a largely 2 track railway (for example) even if he has opportunity to pull aside a late running slow stopper to let an on-time fast through from behind it, he won't as NR will become responsible for the extra delay caused to the stopper.

Some Manchester area signallers were being particularly vociferous on the matter just before Christmas on another forum.

 

[hairyhandedfool]

I guess that all comes down to delay attribution and potential delay further down the line.

I'm far from an expert, but if a Cross Country service is delayed behind Northern stopper and as a consequence causes delays in the Birmingham area, and then in the South West, it might have been better to let the fast train through and pay for the four or five minute delay on the stopper.

That said, if it was the stopper that was delayed, it might be better to delay that further, rather than have a Cross Country service being delayed.

 

[Minilad]

I guess that all comes down to delay attribution and potential delay further down the line.

I'm far from an expert, but if a Cross Country service is delayed behind Northern stopper and as a consequence causes delays in the Birmingham area, and then in the South West, it might have been better to let the fast train through and pay for the four or five minute delay on the stopper.

That said, if it was the stopper that was delayed, it might be better to delay that further, rather than have a Cross Country service being delayed.

Oh how I wish that was true. Unfortunately these days it is all down to delay attribution and nothing about keeping trains moving and giving them a chance to keep to time. Stuff connections for people on long distance services just make sure we don't get stung for delay minutes.
What a way to run a railway

 

[The Planner]

It does vary on if there is a proper established regulation policy, but Pumbaa is correct that things tend to go in booked order otherwise the signaller cops for an O coded delay. We disputed one the other day that was given to us, but on checking they were ran out of booked order so we disputed it and it was moved to the signaller, such is the fun of the delay attribution merry-go-round.

 

[driver9000]

I've lost count of the number of times I've been running on time and been held at a junction waiting for a late running class 1 or even a freight! . From my understanding of it, late running long distance trains can cause a ripple effect and cause delay to a train many miles away that it won't even have interacted with or even passed! As an example I saw a train delayed at Drem Junction that was the result of a delay to a train in Leeds. I have seen that if a train may become a PPM failure by running in booked order they can be given priority to run ahead of an on time slower train to enable it to terminate inside of PPM.

 

[ralphchadkirk]

I've lost count of the number of times I've been running on time and been held at a junction waiting for a late running class 1 or even a freight! . From my understanding of it, late running long distance trains can cause a ripple effect and cause delay to a train many miles away that it won't even have interacted with or even passed! As an example I saw a train that delayed at Drem Junction that was the result of a delay to a train in Leeds. I have seen that if a train may become a PPM failure by running in booked order they can be given priority to run ahead of an on time slower train to enable it to terminate inside of PPM.

I think that is it. I was once told by an SET controller that they had traced a delay in Glasgow back to a failure somewhere in Kent!

 

[142094]

This shows how there will always be conflict when signalling and infrastructure is provided by one party and services are provided by others. Very fine line to tread as TOCs could complain that Network Rail are delaying their services to ensure NR pays less compensation out due to delay attribution, whereas other TOCs may complain that they were delayed by a different TOC when they shouldn't have been.

Back in BR days am I right in saying that there was a general hierarchy of expresses being given paths over local services if they were delayed, in order to try and minimise delays further along the route? For example a small delay at Birmingham New Street could snowball into loads of delays at Glasgow Central on a cross-country type service.

 

[TDK]

As far as I'm aware, the general policy nowadays is for the box to signal trains through in the timetabled order, and let the TOCs squabble over the delay attribution. As soon as NR intervene and try and restore the service by 'sensible signalling', they get chinged for delaying trains. Madness.

I'm sure some of the resident siggies on here will be along soon to lambast!

You may find that the cost is the priority, for instance if it is a VT vs a LM the VT will most likely go first if the delay is the fault of NR due to delay attribution costing

 

[Techniquest]

Putting freight in front of class 1 or 2 passenger trains still seems beyond daft to me though. Had it cause 5+ minutes of delay at Hither Green on a 465 I was on from Gravesend to London Bridge in August, quite why a class 6 freight got priority over a class 2 passenger is beyond me.

 

[Tomnick]

Putting freight in front of class 1 or 2 passenger trains still seems beyond daft to me though. Had it cause 5+ minutes of delay at Hither Green on a 465 I was on from Gravesend to London Bridge in August, quite why a class 6 freight got priority over a class 2 passenger is beyond me.

A freight will quite often keep well ahead of a stopping passenger behind it, even if it knocks the passenger for a minute or so initially. Not running the freight might cause bigger delays ultimately (as it can't sit there forever!), and of course if there's something else behind it approaching a junction you might have no choice but to run it. I once read that the chaps at Reading went to great lengths to avoid checking the heavy stone trains, as a minor delay to a couple of passenger trains would be nothing compared to the chaos when the freight would otherwise crawl across the station throat from a standing start!

 

[ChrisCooper]

Putting freight in front of class 1 or 2 passenger trains still seems beyond daft to me though. Had it cause 5+ minutes of delay at Hither Green on a 465 I was on from Gravesend to London Bridge in August, quite why a class 6 freight got priority over a class 2 passenger is beyond me.

Putting Freight infront of stoppers isn't as daft as it seems. Freights once they get moving will just trundle along nicely, and often will be well clear of a stopper after a few stops. On the other hand put the freight behind the stopper and it's going to be stopping and starting all the time, something freight's aren't good at, and can start delaying following trains.

Of cource another problem for regulation can be when a train is not ready to depart on time for whatever reason (usually either awaiting crew or due to a fault). In those cases the signallers can only keep the path open until it will start delaying other trains, at which point they will have to allow other trains to run on time infront, and do their best to fit the train if and when it finally is ready to depart. This can lead to stupid situations where a fast train ends up following something much slower, but the alternative would be to have delayed the slower service too. Sods law though says that as soon as the route is set for another train to run ahead of the problem train, the problem will be resolved.

 

[Techniquest]

Sounds about right with regards to Sods Law there, based on past SimSig sessions! Good points though about the freight, although you can imagine sitting on a non-air conditioned train in rather hot weather for what I think was close to 10 minutes in the end (we had waited for at least two expresses as well) was really not welcome, especially when I didn't have many refreshments on me.

Not sure if it was hotter outside when walking along the streets of London in high temperatures with luggage or on the Networker mind, close call!

 

[chuffchuff]

Then you get the case where you let the class 1 past the stopper,
and class 1 has got no relief, so it's sitting there waiting. Guess where the
crew are?
Yup on the stopper that can't get in because the platform's blocked
Good for getting Sig/men swearing over the radio