If you are getting the issue of ‘departure time is in the past’ when attempting to book a journey then it is likely an issue with your time zone settings.
Go to Settings > General and check that the time zone is correct for your location. Ensure that you select a location for the time zone, not a UTC offset. This ensures the time will change with any alterations to time zone throughout the year, for example with daylight saving time. If your city is not on the list, select the nearest one with the same time zone.