Disparity between platform indicator and live departures web page.

[sprunt]

I catch a train from Hornsey to Moorgate each morning, and from where I stand on the platform I'm unable to see the extreme right of the platform indicator. This morning, I could see that the next train was delayed, but the expected arrival time wasn't visible - I could only see the "Exp" in "Expected", so I loaded the live departures page for the station on my phone to see if it was a serious delay. On there, the train was still shown as being on time.

How does this happen? It was only delayed by a couple of minutes, so I'm not angry about it, I'm just curious. I would have assumed that both the platform indicator and the live departures page would take their data from the same source, is this not the case? Or does the departures page only refresh its data intermittently, so that a delay like this that only pops up shortly before the train is due would not be reflected?

 

[yorkie]

Can you provide a link to the live departures page? e.g http://iris2.rail.co.uk/tiger/rendercissod.asp?file=30842B.xml&width=full

While the data itself may be from the same source, the website may be programmed to show a sub-2 minute delay as "on time".

 

[sprunt]

It was just the mobile version of the national rail live departure board - http://m.nationalrail.co.uk/pj/ldbboard/dep/HRN.

The explanation about showing short delays as on time makes sense, thanks.

 

[kieron]

I don't think it's right, though. The nationalrail.co.uk site does (or, at least, did) list different delays to trains on its journey planner to those it gives on its live departure board page. I don't know if this is a difference in the data each uses or in the way it interprets it, but my experience was that the live departure board was more likely to report a delay accurately than the journey planner.

It could be worth checking both pages the next time this sort of thing happens, anyway.

 

[BluePenguin]

It is a coincidence that you posted this question as it something I have wondered and wanted to know the answer for a while. There are lot of stations where trains show on the display board as "arrived" when they haven't

 

[BluePenguin]

Can you provide a link to the live departures page? e.g http://iris2.rail.co.uk/tiger/rendercissod.asp?file=30842B.xml&width=full

While the data itself may be from the same source, the website may be programmed to show a sub-2 minute delay as "on time".

How do you find the departure boards like this one for the stations?

 

[Darandio]

How do you find the departure boards like this one for the stations?

http://iris2.rail.co.uk/tiger/

 

[swt_passenger]

It is a coincidence that you posted this question as it something I have wondered and wanted to know the answer for a while. There are lot of stations where trains show on the display board as "arrived" when they haven't

I think it’s because the signalling system cannot necessarily resolve the train position accurately enough. Arrived may well be displayed as soon as a train enters the track section that includes the platform. In two aspect areas that can be a few minutes away.

On my local line (Fareham to Southampton) RTT is presently showing a service ‘arriving’ at both Netley and Sholing at the same time. This was previously explained to be because both stations are in the same signal section.

 

[whhistle]

I think it’s because the signalling system cannot necessarily resolve the train position accurately enough. Arrived may well be displayed as soon as a train enters the track section that includes the platform. In two aspect areas that can be a few minutes away.

On my local line (Fareham to Southampton) RTT is presently showing a service ‘arriving’ at both Netley and Sholing at the same time. This was previously explained to be because both stations are in the same signal section.

This is correct.

The CIS systems (that drive most websites, apps and stations) all run off signal blocks. So a train may show as "arrived" even though it's round the corner. Similarly railway mapping systems (such as CCF and P2) are the same. There is a public version online that works in the same way.

How do you find the departure boards like this one for the stations?

Not available for many stations though, which is a shame.
I wonder if that's because Worldline provide the service. If the company doesn't pay for support from Worldline (for CIS or ticket machines), they (Worldline) wouldn't bother to code in a station CIS.

 

[RailAleFan]

There is a little more resolution than the train simply entering the track section containing the platform as the timing of that event is adjusted using data from SMART, essentially a database of offsets in seconds (positive and negative) from the time of a berth transition to an actual event occurring (e.g. arrived at XYZ platform 1).

If that happens to be in the future, Darwin doesn't wait until the actual time has been reached before broadcasting it, from which clients can then differentiate between "Arriving" / "Arrived" if desired.

 

[underbank]

How does a "ghost" train occur? I.e. on real time trains and physically on the route, stopping at stations, but not shown on any of the departure boards hence lots of confused passengers when a train arrives at the platform that's not on the screens.

 

[Loop & Link]

Trains can be ‘hidden’ or deleted on CIS from the remote systems.