Re: [MTAdev] Mismatch between GTFS static and GTFS-RT data

[Shen-Cruz, Dillon]

Hi Marco,

Thanks for reaching out. Unfortunately, it is not always possible to directly match Subway and SIR trips between static and realtime data. We do provide a TripReplacementPeriod entity which defines the time range currently covered by the realtime feed.

Generally, GTFS-RT consumers can attempt to match realtime and static trips on a best-effort basis, but should be prepared for the possibility of unmatched realtime trips. This occurs due to the nature of our transit operations and the software we use to operate the subway. On any given day, the schedule may be modified—to support planned work or other operational needs, or to respond to incidents and other realtime conditions—and these will all result in trips appearing in realtime data which cannot be matched to the static schedule.

You can find more details in our GTFS-realtime Reference for the New York City Subway documentation. Please feel free to follow-up here with additional questions.

Thanks,

Dillon

Dillon Shen-Cruz (he/him) 

Metropolitan Transportation Authority 

Product Manager, Data and APIs

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From: 'Marco Graniero Celis' via mtadeveloperresources <mtadevelop...@googlegroups.com>
Sent: Thursday, July 24, 2025 16:53
To: mtadeveloperresources <mtadevelop...@googlegroups.com>
Subject: [MTAdev] Mismatch between GTFS static and GTFS-RT data

 

Hi,

This is Marco from Transit's realtime data team.

We've noticed that SIR's GTFS-RT (https://api-endpoint.mta.info/Dataservice/mtagtfsfeeds/nyct%2Fgtfs-si) tripIds are not matching the expected static trip_ids. We do some cleaning to extract the RT trip_ids from the static data (for example, from L0S5-SI-2017-S06_147100_SI.N03R to  147100_SI.N03R).

However, at the moment we aren't getting any matches. For example, the tripUpdates entity below (tripId 099300_SI.S03R) doesn't have any matching counterpart in the static data:

    {
      "id": "000005SI",
      "tripUpdate": {
        "trip": {
          "tripId": "099300_SI.S03R",
          "routeId": "SI",
          "startTime": "16:36:00",
          "startDate": "20250724"
        },

Would it be possible to have someone have a look at this issue?

Thank you for your help!

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