Train Derails In Free Roam

When I drive in free roam scenario for 15-20 minutes "player train derailed" message suddenly appears. It doesn't look like it really derailed. The train just stops while driving. I tried to remove all other trains from scenario, but that didn't help.
Sorry for my bad English

 

Does it happen when rolling over a switch? If so, it probably isn't aligned correctly. Make sure all the switches are properly set before moving. You can do this by pressing 9 and then following the blue line to ensure that everything is in order.

 

Unfortunately no. On straight track. I tried to find something in the Internet but there is no info about that

 

Even on straight track there can be deviations of crossovers... recreate and screenshot?

 

I went to the city, maybe I will send screenshot tomorrow or late evening.
Just straight track in empty world also causes derailment

 

We don't know which loco on which route etc yet so it's hard to give proper support...