There's both: GTFS is a standard for the regular schedule, and GTFS-RT is a standard for realtime information. Link: https://gtfs.org/documentation/realtime/re

There's both: GTFS is a standard for the regular schedule, and GTFS-RT is a standard for realtime information. Link: https://gtfs.org/documentation/realtime/reference/ https://gtfs.org/documentation/realtime/reference/