GTFS
GTFS (General Transit Feed Specification) is an open format for describing stop locations, schedules, etc.
It resulted from a collaboration between Portland-based transportation company TriMet and Google in 2005.
https://developer.trimet.org/GTFS.shtml
To popularize and control the development of the format, the company Mobility Data was created.
https://database.mobilitydata.org
More than a thousand transportation companies provide data in this format
to developers and companies.
The data are distributed as a ZIP archive with CSV files: stops.txt,
routes.txt, trips.txt, shapes.txt, calendar.txt, …
https://developers.google.com/transit/gtfs/reference
Especially curious to me is the GTFS-Pathways
format extension (pathways.txt) describing the multi-level stations, transfers, and boarding zones.
