Late running trains that disappear off departure boards

[TUC]

On several occasions at different stations I have noticed late running trains disappear off station departure boards after they are more than a few minutes late, even though they have actually not yet arrived at the station.

One example was this morning. I arrived at Sowerby Bridge around 0749 and the departure board was showing the next train to Leeds as being the 0759. However, a couple of minutes later, the late running 0748 arrived.

Given there was no announcement at the station or on the train and it was not on the departure board, this could have proved a trap for those unfamiliar with local services as the 0748 goes via Dewsbury whilst the 0759 goes via Halifax. Therefore, anyone thinking this was the 0759 coming in early (given it was the next train on the departure board) would have been in for a nasty shock!

Just as oddly, on a number of occasions, these trains also cease to show as awaiting arrival at the station on RTT and give the impression they have departed the station in question (for which I'm not criticising RTT. I recognise it is only pulling data from elsewhere.)

Why does this occur and why is it only certain stations where it seems to be an issue?

 

[thejuggler]

It happens because the system isn’t very good!

Just last week my train was showing 5 minutes late. It then disappeared as though cancelled, making out the next service was half an hour later.

One passenger was about to leave to get a taxi. A quick look of RTT and the service had left Leeds 7 minutes late and was still running.

 

[TUC]

It happens because the system isn’t very good!

Just last week my train was showing 5 minutes late. It then disappeared as though cancelled, making out the next service was half an hour later.

One passenger was about to leave to get a taxi. A quick look of RTT and the service had left Leeds 7 minutes late and was still running.

But how can that happen if RTT and the station system are drawing from the same data source?

And how can a late running train disappear (which I agree happens, but why?)

 

[Mutant Lemming]

At St.Pancras on-time trains disappear too - especially when they end up near the bottom of the departures boad.

 

[methethpropbut]

A friend got into this mess at Meadowhall where the late-running stopper to Leeds and the subsequent skip-stop service to... well, Leeds (!) got entangled and swapped positions - not fun for the many who needed to get to Chapeltown and instead went right through it

 

[ComUtoR]

But how can that happen if RTT and the station system are drawing from the same data source?

Because one is an active system that shows current data. The other shows historical data.

I'm not sure that a CIS board is capable of showing trains from 4/5 days ago or keep train data from hours ago showing. :/

 

[infobleep]

Because one is an active system that shows current data. The other shows historical data.

I'm not sure that a CIS board is capable of showing trains from 4/5 days ago or keep train data from hours ago showing. :/

During disruption or even after, it's not been unheard of for CIS to display older train running info. These daya it's not so common as it use to be.

 

[XCTurbostar]

As a general rule of thumb, in delay periods, trust RTT more than the display except for departing platforms.

 

[robbeech]

As a general rule of thumb, in delay periods, trust RTT more than the display except for departing platforms.

This is all well and good but if you find yourself in a predicament due to missing a service you’re much more likely to get help from Station staff if you’ve read incorrect displays than incorrect RTT data.

 

[TUC]

Because one is an active system that shows current data. The other shows historical data.

I'm not sure that a CIS board is capable of showing trains from 4/5 days ago or keep train data from hours ago showing. :/

I'm not talking about 5 days ago. I'm talking about 5 minutes ago!

 

[TUC]

As a general rule of thumb, in delay periods, trust RTT more than the display except for departing platforms.

Given that most passengers will (understandably) look at the display rather than RTT, that really isn't an acceptable state of affairs.

 

[Taunton]

This arises due to the programming of the CIS having been done by those who don't understand railways.

Another example is London Waterloo, where it was determined that trains would be removed automatically from displays 1 minute before departure, to aid dispatch punctuality. This includes right at the platform entrance where the train doors are right in front of you. All well and good where trains are perfectly to time (Ha Ha), but where they are being delayed in departure and the doors remain open it's a nonsense. In the extreme, I've seen trains cleared before the inbound working has yet arrived.

Departing Waterloo on the morning of the sideswipe derailment a few months ago it was apparent that such automated systems just cannot keep up where it comes to major disruption. Very substantial sums are paid out to the suppliers of such systems, but they seem to spend all the money on the hardware and any practical thought about what might be displayed is squeezed in at the end.

 

[skyhigh]

Another example is London Waterloo, where it was determined that trains would be removed automatically from displays 1 minute before departure, to aid dispatch punctuality. This includes right at the platform entrance where the train doors are right in front of you. All well and good where trains are perfectly to time (Ha Ha), but where they are being delayed in departure and the doors remain open it's a nonsense. In the extreme, I've seen trains cleared before the inbound working has yet arrived.

The same happens at Leeds, although if the train is shown as 'Expected XX:XX' or 'Delayed' it won't clear off the board until that time/message changes, rather than the scheduled time. Surely that would be sensible, unless I'm misunderstanding?

 

[BurtonM]

The boards at Manchester Oxford Road get really confused by delayed trains.
They only show the next train. If a train is delayed past the time of the train that’s supposed to be behind it, the board decides of its own accord that the second train is coming first because it’s still ‘on time’ and switches to display that for a few minutes. Cue a load of confused passengers wandering off to find a departures board to see where their train has gone. It changes back when the residual delay is applied to the second train and it’s put back in its right place in the queue.
If a delay keeps increasing by small amounts the problem is made worse as the board then changes to the wrong service about a minute before the second train’s original departure time (and usually by this point the first service is about two minutes away), and the system hasn’t always clocked the residual delay on the second train by then (not that it matters). Again, people get confused and wander off only for the boards to change back to the right service when the right train shows up as the correct service arriving triggers an announcement, and the board going back to the right train with ‘arrived’ now showing.

 

[jon0844]

At Knebworth, trains can be shown out of sequence even when you can see that there's no way train X can overtake train Y through the Welwyn viaduct, but it isn't until the train reaches another track circuit or station that the train behind is given the necessary delay minutes to put it back in the correct position.

Darwin is quite clever most of the time, but clearly doesn't have the ability to look at a route map and see that there's simply no way some trains can beat another.

 

[DanTrain]

Was standing at Sheffield Uni tram stip yesterday and a Yellow line service appeared having been unindicated by the board, I assume it was running late. Threw me off a bit though as it said my tram was only 1 min, fortunately the trams are well labelled on the front.

 

[JN114]

I think there’s a fundamental misunderstanding on how majority of CIS systems work going on here - and thus not appreciating how they can fall down.

Most systems have a database; (these days linked to the Darwin master database). The database contains the timetable; and then various pertinent bits of information about each train - how long it is, where and when it was last reported to be, and the time delta at that location vs expected.

Each individual screen is then like an individual computer; logged into the database and reading information from it. A typical 3 line platform display will query the database for the next 3 trains at that platform at that station and show them in the order.

If you have a late running faster train following a slower one; the fast one will show as the first train as the system can only show its current delay automatically; it doesn’t know it’s not possible for the two trains to overtake. Once the slow train reports as arrived at the station; then the screen will usually update.

To the OPs example - train disappears before arriving - that’s usually a consequence of a train reporting arrived at a timing point further along the line. Likely TRUST or similar auto reporting isn’t quite set up right; or accounting for the train losing as much time as it is; so the train reports arriving so the CIS database skips along to that timing point in the TT. When I used to do CIS for my employer it was one of the conversations I’d have with signalmen - they would, well meaningly, input the TD at station E to enact a platform change without having to phone me. The problem is the train is still at A; and now TRUST has a TD report at E the train has disappeared from screens at B, C and D.

 

[TUC]

I'm currently on the 1603 Kings Cross-Bradford waiting outside Wakefield Kirkgate as, due to a train blocking the platform, our train will have to reverse into a different platform. However, the train has disappeared off RTT in terms of Wakefield (and, as said above, I know RTT is only as good as the data it pulls from, but it does highlight there is an imperfection in the underlying system.)

 

[TUC]

I'm currently on the 1603 Kings Cross-Bradford waiting outside Wakefield Kirkgate as, due to a train blocking the platform, our train will have to reverse into a different platform. However, the train has disappeared off RTT in terms of Wakefield (and, as said above, I know RTT is only as good as the data it pulls from, but it does highlight there is an imperfection in the underlying system.)

And has now reappeared after getting to the station!

 

[cin88]

Darwin basically loses it's head as soon as a delay starts to cross over into whatever the next train on the timetable is. Station comms staff can normally force the CIS to display the correct train when it gets this way.

 

[74A]

The system is just doing the best it can with the data it receives. There are only a limited number of timing points on the rail network. So for example a train leaves a station 6 minutes late. There are no further timing points before it arrives at the next station. So the system just has to assume that after 6 minutes of delay the train must have left so will remove it from the departure board even if the train has not arrived yet.

This happens at places like Stroud and Kingham.

 

[Parallel]

The system is just doing the best it can with the data it receives. There are only a limited number of timing points on the rail network. So for example a train leaves a station 6 minutes late. There are no further timing points before it arrives at the next station. So the system just has to assume that after 6 minutes of delay the train must have left so will remove it from the departure board even if the train has not arrived yet.

This happens at places like Stroud and Kingham.

Also at Westbury and some stations on the ATW network like Cardiff Central and Shrewsbury.

 

[TUC]

The system is just doing the best it can with the data it receives. There are only a limited number of timing points on the rail network. So for example a train leaves a station 6 minutes late. There are no further timing points before it arrives at the next station. So the system just has to assume that after 6 minutes of delay the train must have left so will remove it from the departure board even if the train has not arrived yet.

This happens at places like Stroud and Kingham.

So surely the answer is to have timing points, and the requisite detection, set for just after where a train leaves a station?

 

[JN114]

So surely the answer is to have timing points, and the requisite detection, set for just after where a train leaves a station?

That would be the ideal from a CIS standpoint; but it just doesn’t work like that in practice. The automatic train reporting system is designed for recording train running against the central timetable database. Automated CIS systems are a handy bolt-on consequence of that technology. Specific infrastructure for CIS reporting would largely duplicate existing systems; and therefore would be £££ for only minimal benefit.

Current systems have their shortcomings; but those are well known by the industry and mitigations are made.

 

[IanXC]

So surely the answer is to have timing points, and the requisite detection, set for just after where a train leaves a station?

These systems almost all make use of data already collected by the signalling system, adding in whole detection systems for the purpose of improving information would be a hideously expensive operation.

That said, there are a few examples of equipment to do this. Usually these are based on detecting the presence of a train, and the subsequent non presence of a train, however they rely on the trains arriving in the booked order, or having a time input from some other source, at the location where they are being detected. This, not infrequently, goes wrong meaning that arrival/departure times get allocated to the incorrect service until someone resets the location.

 

[TUC]

This morning at Mirfield both the 0636 to Leeds and the 0640 to Wakefield Westgate were running a few minutes late. Both the display and the announcements were saying that the next train to arrive would be the Leeds one-until 0640, just when the Leeds train was pulling into the station. At that moment the display changed to
1st train: 0640 Wakefield Westgate
2nd train: 0636 Leeds.

It was actually the Leeds train that was arriving, but unless passengers saw the destination on the front of the train Im left wondering how they were meant to know for sure!