Preview available: Commuter rail arrival/departure change

[Developer at MBTA]

All,

Earlier this year we changed commuter rail predictions from arrival-time to departure-time, then rolled that change back and promised a variation of it in the future with separate arrival and departure times. That variation is now ready; you can access a test feed that includes it now and we will deploy it to production next week.

This change does not affect the v2 API (it will be in future API updates), only GTFS-realtime TripUpdates, and within that, only commuter rail StopTimeUpdates. Commuter rail StopTimeUpdates will no longer necessarily have identical "arrival" and "departure" StopTimeEvents. Sometimes the arrival time will be earlier than the departure time. This reflects cases when the train is predicted to arrive early at the station, but the train is scheduled to hold once it gets there rather than leave early. This is the normal commuter rail procedure, so this applies to all commuter rail stops except those for which GTFS "timepoint" is false (those noted with an "L-note" on the schedule, or the last stop of the trip.)

You can preview the change here:
http://23.21.118.89/Portal/Content/GTFS-realtime/TripUpdates.pb
Please disregard any differences you notice in the data for other modes. 

Please provide any feedback you have, and we'll update this thread with the scheduled launch time. Thanks!

Sincerely,
developer@mbta

[Developer at MBTA]

This change will go into production late Thursday morning.

Sincerely,
developer@mbta

[George Wright]

Likewise, for L-stops, if the train is running early, will predicted departure match predicted arrival?

Thanks

On Tuesday, September 5, 2017 at 10:16:03 AM UTC-4, Developer at MBTA wrote:

[George Wright]

Not to ask an obvious question, but if the trip is running five minutes late, would we expect to see the arrival and departure times both delayed simultaneously by five minutes?

On Tuesday, September 5, 2017 at 10:16:03 AM UTC-4, Developer at MBTA wrote:

[Developer at MBTA]

For an L-stop, or if a train is running late and is projected to arrive at a station after its scheduled time, then the values for arrival time and departure time will be equal.

Sincerely,
developer@mbta

[Developer at MBTA]

This change is now in effect.

Sincerely,
developer@mbta

[RideSchedules Webmaster]

Goodie.