So here is my issue..
Whenever I select a consist to run on in Quick Drive, everything loads up fine without errors. But eventually, after running the train for about four miles or so, I get the derailment camera (view that spins around the lead locomotive) and I get the derailment message. Nothing was in my way, or collided into me.
Later on, I discovered that this problem was not a bug with the route, because while I was driving another train on the Sherman Hill route, I derail out of nowhere and get the error message.
Eventually I decided to stop using Quick Drive and create my own Free Roam scenarios (on Coal District, Sherman Hill, Marias Pass, and New York-New Haven) to see if this method would get rid of the annoying bug. Nope! My train still derails about four miles from the starting point! Nothing was in my way, a switch was not lined against me, and there was not another train that collided into me. I just randomly derail whenever I'm minding my own buisness!
Is anyone else experiencing this issue with TS2015? If not, does anyone have any ideas that may get rid of this problem? Thanks in advance.