In the recent weeks, I have seen jumping trains in many occasions, causing network problems and lockups. But their increased occurrence may happen only due to an higher speed and density of trains combined with a much more complex network than before. On the other hand, I remember jumping trains from previous years of ST experience.
Where jumping definitely occurs:
- using "send to depot button" (additionally: if the depot is near enough, the train head jumps into it, but the train remains on the track); modifying the schedule instead causes the convoy to stop anyway, so jumping does not happen there.
- waypoints (sometimes with improper clearance of reservations, which might be caused by non-standard wagon length)
- track layout changes (but this is expectable)
- line schedule changes - it would make sense to stop the trains (of the line) entirely before rerouting
Where jumping may occur as well:
- loading and/or saving
- high CPU load or bad response/refresh times
It is fairly normal that a jumping train resets its reservations and ignores halt signals. Also, most of these cases may lead to recalculation of routes after the route has already been changed temporarily by a choose signal, so the train effectively passes a halt signal and tries to get into an occupied track, causing a deadlock if it is a dead-end station/track.