Incorrect Grand Central Shuttle Documentation & Data

[Underway]

hello,

I have consistently observed a documentation error and data error over the past several months regarding the Grand Central Shuttle in the GTFS feed.

Documentation error

In addition, the documentation in `https://api.mta.info/nyct-subway.proto.txt` says the opposite of what I usually observe, confirmed with arrival times on `new.mta.info`. I usually observe the following:

N = to Times Square

S = to Grand Central

Data error

In the GTFS Real-time feed, the NYCT Trip descriptor sometimes contains "SOUTH" for the direction, when the `trip_id` indicates `N` for north, for the Grand Central Shuttle aka `GS`. Since this happens inconsistently, I suspect it is in error. 

For a workaround, I will use the trip_id to get the direction of the train. 

Screenshot: 

Text of entity:

entity {

  id: "000156"

  trip_update {

    trip {

      trip_id: "136000_GS.N01R"

      start_date: "20220710"

      route_id: "GS"

      [transit_realtime.nyct_trip_descriptor] {

        train_id: "0S 2240  GCS/TSS"

        is_assigned: true

        direction: SOUTH

      }

    }

    stop_time_update {

      departure {

        time: 1657507200

      }

      stop_id: "901N"

      1001 {

        scheduled_track: "1"

        actual_track: "1"

      }

    }

    stop_time_update {

      arrival {

        time: 1657507290

      }

      stop_id: "902N"

      1001 {

        scheduled_track: "1"

      }

    }

  }

}