Greetings!
I have seen cases of trains driving under token block signalling method reverting to drive by sight after loading of a game. Here is a save-game where I can observe this: http://files.simutrans.com/index.php/s/lqcZACkO4yC1EBO
Here is a screenshot of what I see when I load the above game: http://files.simutrans.com/index.php/s/HnuFROJKAPl3ylD
How to reproduce:
1. Load above saved game.
2. Pause the game as soon as it has loaded. Need to be fast to hit pause because I see the train switching from token block method to drive by sight very soon after loading.
3. Best hit Shift-B to show track reservations.
4. Scroll map a little to north and east, following the train track.
5. The first train you see will be vehicle No. 4, it shows for me as if the loading of the game has caused a schedule change of some sort, the last few wagons of the train display off-track for me. (see above screenshot)
6. Note that track in front and behind of the train is correctly reserved under token block method.
7. Open train info window, open detail window of train info. Token block should be specified (as in sceenshot as well).
8. Un-pause game and see signalling method change to drive by sight in detail window.
Edit: I have seen this only under token block, absolute block and one train staff methods work fine on that map.
I think that I might have fixed this (and some related problems caused by loading saved games where some convoys were on diagonal ways); would you be able to re-test with the next nightly build? I should be most grateful.
Looking good! Have so far seen no new cases of this. Saved and loaded about 10 games with trains on diagonal tracks. No problem seen.