VALIDATION: (stop_times) stop_headsign

[jlundan]

• This field overrides the default trips.trip_headsign when the headsign changes between stops. If the headsign is displayed for an entire trip, trips.trip_headsign should be used instead.
• A stop_headsign value specified for one stop_time does not apply to subsequent stop_times in the same trip. If you want to override the trip_headsign for multiple stop_times in the same trip, the stop_headsign value must be repeated in each stop_time row.