Two trains at 1 sec difference in central platform 21


Hi Team,

I have query we are planning to display real time table for sydney trains in mobile app. For central platform 21 , we are getting two trains at the same time only line is getting differ from T2 to T8. any Idea which train we need to pick to display in the UI.


Hey @jspadmini,

Would you have some example trip ids? Those two trains should be the same train. Since the Sydney Trains rail network has the City Circle loop, some train services might change route designators upon arrival at Central. The GTFS spec allows these trips to be “joined” together using the block_id field.

As to which one you show, it would depend on whether you’re displaying arrivals or departures. You can use pickup_type and/or drop_off_type to determine if it’s the arriving service or a departing service.

Hope that helps!



Hey Ken - just following up in Jeyaraj’s absence.

Some example trips ID are 113C and 113D, 166C and 166D, etc. It seems like the numbers stay the same but the letter is always sequential. This has mainly been identified for trips at Central station platforms.

Is the block_id the same as the ‘roster’ which details all the trips a train makes in a single day?



Yep, that’s one way to look at it. I suggest taking a look at the Sydney Trains GTFS documentation and Google Transit GTFS documentation if you haven’t already. It should clear things up.


Thanks - really helpful.