It seems that a number of red light issues and locomotive issues can be circumvented by spawning on foot instead of selecting a service from timetable mode. I'm curious as to how this is the case - is there a reasonably simple explanation of why this is so?
My theory is pure speculation. Maybe it has something to do with the starting time. When spawning on foot you can select 5minutes steps, while some services from the menu would kick in the game at 13:27. I always spawn on foot and take over a service, rarely had trouble except the broken substitution in TSW4, which is another topic..
Here's my theory. First, notice you can spawn in at any time in the timetable. How does TSW know where the trains are at a specific time? There is snapshots of train positions, saved in the so called "data tracks". This allows fast loading times, as the timetable does not have to be simulated from start to spawn time. If a service starting time is not saved in the data tracks (for example there's a snapshot of 15:00, service starting at 15:02), the positions of the trains are interpolated to advance two minutes. In some cases, this leads to a train occupying two signal blocks (placed over a signal), which the dispatcher cannot handle as a starting position. The train won't move. By choosing a different time via spawning on foot, this can be avoided. Just a minute earlier and the timetable loads correctly. Zusi3 for example avoids this at the cost of some waiting time when taking over a service that starts hours into the timetable. The tt gets simulated from beginning in fast forward, there's no saved snapshots.
