I have found the same problem and submitted a ticket to N3V because I uninstalled the route reinstaaled it to prove the issue was repeatable. It was so I cloned the sessions found the derailed consists and painstakingily set each car back on the track and saved my clones. Both the cloned sessions work as intended so it is an Issue N3V need to address for their Payware assets.
I have found the same problem and submitted a ticket to N3V because I uninstalled the route reinstaaled it to prove the issue was repeatable. It was so I cloned the sessions found the derailed consists and painstakingily set each car back on the track and saved my clones. Both the cloned sessions work as intended so it is an Issue N3V need to address for their Payware assets.
This derail issue has been generated by SP4. N3V have recorded it as a known issue and are looking to fix it in the next Upgrade for which no date is available. The issue with the tunnels (see the other current thread) was known in SP3 beta stage and I was informed it would be fixed in the SP3 release. It was not and it was not fixed in the SP4 release. So I am not convinced about the N3V support for their payware packages.