Multiple trains in time interval with telegraph occupying the same tile

[freddyhayward]

Steps to reproduce:
1. Open time_interval.sve
2. Follow train number 3 currently waiting at "land stop 4 railway station"
3. Wait until it approaches "land stop 3 railway station"
4. Observe that the signal at (12,14) shows "clear"
5. Observe that trains 1 & 4 already occupy (11,14)
6. Observe that train 3 triggers an emergency stop when passing through (12,14)
7. Observe that train 3 enters (11,14) and triggers a second emergency stop
8. Observe that three trains now occupy (11,14)

Note that this case also shows that time interval with telegraph signals give the clear aspect even when the tiles immediately in front of it are occupied. If this is an intentional feature, it is highly unexpected and should somehow be communicated to players. I can create a separate thread for this if necessary.