[Signaling] Multi-tile trains may not make correct reservations

[Ranran(retired)]

I have often seen trains that have achieved signal working method status, but have not reserved forward.

I have always wondered if this condition would not cause a train collision, but it turns out that it can easily cause a train collision.
I also discovered one of the conditions under which this can happen.
In extended, trains that are shorter than the length of the platform can stop at any tile specified in the schedule. This will cause the station signal to not work properly.
Station signals frequently fail to reserve any tiles ahead of the station signal if the train does not stop at the signaled tile. (It only works properly if the train reaches the station without blockage or stops at a signal tile.)
Therefore, the block can be entered from the opposite side, and may collide with other similar trains, or with trains entering by drive by sight.
In long term play, trains in both directions on a single track section sometimes have head-on collisions in this condition.


In the process of testing this hypothesis, I found a reproduction that definitely causes the bug.

- Download and open this saved game.
- Keep an eye on the reservations between stop1 and stop3.
- There are three types of trains, but one train(DMU) always makes a different reservation than the others.
What makes this DMU different from other trains?

Anyway, there is no doubt that all these convoy reservations should essentially work the same.


You can also check this bug at any time in the demo save.
- Open a demo save, then go to Havenpool Quay Station.
- Wait for the train to arrive there.
- When that train turns back at Havenpool Quay station, the reservation will be cancelled and the train will fall into this buggy state.
- Tile is not reserved, so a head-on collision can occur by letting a drive-by sight train enter from a nearby depot.

[jamespetts]

Thank you for your report. I believe that I have fixed this. I should note that this was actually a separate bug to that in demo.sve - but I believe that I have fixed both of them.

I should be grateful if you could re-test.

[Ranran(retired)]

Thank you for addressing this issue. Some of the strange behavior seems to have been improved. However, I can still see cases where reservations are not performed properly.
Check out the saved game I submitted before. (2) BR Class 139 "Parry People Mover" Whenever the DMU goes from stop2 to stop1, forward reservation is not executed. When check the  track that in front of it, it will show that there is no convoy reserved.

[jamespetts]

Thank you for that report. I believe that I have now fixed this. I should be grateful if you could re-test with the next nightly build.