We are converting TFL txc data (provided as journey-planner-timetables.zip on tfl website) into GTFS and trying to keep the trip_ids stable from one version of TxC data to another. For that reason we used hash values for trips based on the most important data like stop sequence, schedule, calendar days, exceptions and operation start/end dates.
Due to the fact that TFL changes the start date for the same trips quite frequently in the new updated static TxC data our trip_ids change as well. The problem is that the change of the operation start date is sometimes the only change made to the data over a period of time (e.g. 7 days).
What is the reason for this?
Example data examined:
Tram route presented in the file tfl_63-TR-_-y05-14.xml
We compared the data of 20.05.2021 and 02.06.2021
We made a comparison of 2 files and some other cases as well. Nearly in 9 cases out of 10 the only change is the Operating period start date
Thanks in advance,