train departure info in stations on the screens

[petemurphy]

you know the screens on the station platforms...how are they updated is there a bloke in the station or is it done centrally? Any ideas on what system its done?

[blueg33]

On the line I use it is apparently automatic based on a sensor and estimated time between sensor and station.......its wrong more often than it is right!

It appears to be a different system to that used by National Rail enquiries as I get different answers on my Blackberry app compared with the screens in the station. Blackberry app is more accurate as a rule.

Currently typing from a train that is 10 mins late according to Blackberry and my watch, but was on time accoring to station display until it arrived when it was shown as 5 minutes late!

[petemurphy]

hmm i thought they may be more accurate as the network rail site says all our trains are running yet the south eastern one says none are!! why cant they stick gps on the trains so everyone knows where they are!

[AV12]

They majority of the newer trains do have GPS, thats how you get the automated train announcements. I think the confusion is somewhat deliberate. It's all about stats, you know.

Its confusing as the LDB says they are running a normal service, but really it's half hourly.

[Simpo Two]

blueg33 said:

Currently typing from a train that is 10 mins late according to Blackberry and my watch, but was on time accoring to station display until it arrived when it was shown as 5 minutes late!

AV12 said:

I think the confusion is somewhat deliberate. It's all about stats, you know.

I immediately thought the station display was connected to a 'target counter' too...

A good cause for nationalisation IMHO.

[anonymous-user]

AV12 said:

Its confusing as the LDB says they are running a normal service, but really it's half-arsed.

EFA.

[AV12]

To add, the whole TOC/NR - they get away with blue murder.

According to their policy, over 10 minutes is late. That would be unacceptable anywhere else.

[blueg33]

AV12 said:

To add, the whole TOC/NR - they get away with blue murder.

According to their policy, over 10 minutes is late. That would be unacceptable anywhere else.

Firs Great Western is not late enough for a refund until its an hour late! Thats enough to seriously stuff up your working day

[Nigel H]

To answer the original question it depends where you live. For me in essex the train departure information is taken from the track circuits on the rails, which gives a pretty good answer of when the trains will arrive. When the service goes wrong then the predictions become less accurate as they use the average time from where they are to their next arrival point.

This is completely independent of the systems on the trains. As others have said the more modern trains use gps to drive the on board train information, older trains use tachos on the end of the axles to calculate distance. This is less accurate than gps.

[28V6]

Also where older manual signalling stills exists, the arrival/departure and passing times are inputed by the signalman into a system called T.R.U.S.T which then updates the passenger information screens at stations.