Hello HaggisMan59
TT (post from mrbeans04) certainly means the "TTData" folder, which can be found in the Berlin-Spandau map folder. All timetable files are stored there. This has nothing to do with the settings in OMSI. As you have recognized yourself, you shouldn't change anything when starting via the BCS.
This error message appears if a tour/map/timetable/line-pack is not installed correctly or if you have set a map/line to the ignore list in the BCS. Since this is a standard line from the standard OMSI map Berlin-Spandau, we can rule out a line-pack.
The map Berlin-Spandau exists in several "versions" in OMSI, which play in different years. In multiplayer, however, only the very latest/newest/most recent version is playable (I think it must be 1994).
1. Could it be that you put this map on your ignore list?
2. If not, your game or the Berlin-Spandau map may not have been installed correctly or is defective. In such a case, I would first try to repair OMSI via Steam. Normally the error should then be fixed.
3. If that still doesn't help, you can try to uninstall OMSI (uncheck OMSI on Steam (OMSI only)), then manually delete the Berlin-Spandau map folder, and then have OMSI reinstalled via Steam.
At the same time, I passed this on to a colleague from the trip team. He'll take a look at it in the next few days to be sure. But please be a little patient!