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Describe a frequency-based service

The Société de Transport de Montréal operates transit services in Montréal and runs a frequency-based service for its métro lines. Hence, instead of providing a schedule with arrival and departure times in a GTFS dataset, the file frequencies.txt is used to describe the service frequency throughout the span of the service.



Above, a trip on the Green line with a trip_id=22M-GLOBAUX-00-S_1_2 is used as an example. For that trip, the first record indicates that between 4:01:25 PM and 4:19:25 PM, trains run every 180 seconds (or 3 minutes). Similarly, the second record indicates that between 4:19:25 PM and 5:03:25 PM, trains run every 165 seconds.

Example source