Uniquely identifies a set of dates when service is available for one or more routes. Each service_id value can appear at most once in a calendar.txt file.

Indicates whether the service operates on all Mondays in the date range specified by the start_date and end_date fields. Note that exceptions for particular dates may be listed in calendar_dates.txt. Valid options are:

1 - Service is available for all Mondays in the date range. 0 - Service is not available for Mondays in the date range.

Functions in the same way as monday except applies to Tuesdays

Functions in the same way as monday except applies to Wednesdays

Functions in the same way as monday except applies to Thursdays

Functions in the same way as monday except applies to Fridays

Functions in the same way as monday except applies to Saturdays.

Functions in the same way as monday except applies to Sundays.

Start service day for the service interval.

End service day for the service interval. This service day is included in the interval.