How do open data train time sites work?

[ANDYS]

Thanks to the advent of programs like Real Time Trains we now have lots of info available when travelling the country. But how does it work?

On aircraft they have a transponder which basically sends information identifying a particular aircraft. I am into the aviation side of this big style so I can see that British Airways A321 G-EUXD is currently flying high over my house. My little SBS box decodes all this and then I share my data (via sites such as Flightradar 24) for the benefit of everyone who is interested.

On train sites, I understand that the signalling data is used and this gives the basic information about a train being within a signalling section. However, how is a particular train identified. How do I get to know that train 1F63 is the train that is sitting in the signalling section at Chesterfield?

Any help gratefully received, Andy S

 

[najaB]

On train sites, I understand that the signalling data is used and this gives the basic information about a train being within a signalling section. However, how is a particular train identified. How do I get to know that train 1F63 is the train that is sitting in the signalling section at Chesterfield?

Any help gratefully received, Andy S

Have a look here and here.

Edit: Oh, and here for an intro to what the datasets are.

 

[PHILIPE]

And here where there is a thread on Real Time Trains

www.railforums.co.uk/showthread.php?t=123699

 

[ANDYS]

Cheers najaB

This looks very complicated. I will have a look through this and try and get my head around it.

Whilst I do that, can you (or anyone else) explain how a train transmits its identity? I had never thought about it until today and never thought that they do. However, I can only assume that they must otherwise the signalling system would only know that a train was in a section, not which train. Am I right or miles off?

Andy S

 

[najaB]

Whilst I do that, can you (or anyone else) explain how a train transmits its identity? I had never thought about it until today and never thought that they do. However, I can only assume that they must otherwise the signalling system would only know that a train was in a section, not which train. Am I right or miles off?

You're a little off the mark. If you know what train it is entering a section, you can be pretty sure what train it is leaving a section. So it's just a case of entering the correct ID into the first berth, and knowing what route has been set at the exit so that you can update the next berth with the correct train ID.

Edit: You might notice on the thread PHILIPE linked, that Tom who runs Realtime Trains is a member here, though he doesn't post very often.

 

[Freightmaster]

...how does it work?

On aircraft they have a transponder which basically sends information identifying a particular aircraft.

Further to Naja's reply above, it should be stressed that unlike planes
and ships, trains do not 'broadcast' their identity or location, so real
time information relies almost entirely on information from signalling
systems, either:

a) manually by signallers inputting the passing times into TRUST

b) automatically, by trains occupying track circuit 'berths'



MARK

 

[D1009]

Cheers najaB

This looks very complicated. I will have a look through this and try and get my head around it.

Whilst I do that, can you (or anyone else) explain how a train transmits its identity? I had never thought about it until today and never thought that they do. However, I can only assume that they must otherwise the signalling system would only know that a train was in a section, not which train. Am I right or miles off?

Andy S

Traditionally every train's identity had to be entered by the signaller on his panel from information extracted from the Working Timetable. The signalling system automatically forwards this data to the next panel as the train progresses. In the more modern signalling installations nowadays the initial information comes from a timetable database produced by the train planners.

 

[ANDYS]

Thanks everyone for the info.

I did not think they transmitted their identity but, as I said in my original post, I had never thought about it before. It was as I was sat on a train yesterday watching my progress both in the real world and the virtual world that I suddenly began thinking.

Thanks all, Andy S

 

[najaB]

Has anybody tried playing around with the data feeds? I've been mucking about with them over the last couple of evenings and I've been trying to use the train movement feed to build a live(ish) map of Scotrail trains.

One thing I've noticed is that the train_terminated field of the train movement message seems to be set when it shouldn't be. Anyone else noticed this?
--- old post above --- --- new post below ---

One thing I've noticed is that the train_terminated field of the train movement message seems to be set when it shouldn't be. Anyone else noticed this?

Okay, never assume data types - turns out that a true/false variable was actually a string!