Steam Scenario Ends Because Of Some Derailing (airedale & Wharfedale)

Platform: PC / Steam
Game Version: TSW 7 Deluxe
Route: Airedale & Wharfedale Network
Scenario: Timetable, Service 2S08 (Class 333 from Bradford to Skipton, departure 08:08).
I took over the train at Frizinghall after driving as passenger (before that I took service 2P24 from Leeds to Bradford)
What happened:
arrived at Keighley, opened the doors, then after closing doors the scenario suddenly was stopped/finished because of some train derailed(????). I was still standing!!! So I have no clue what or who was derailed.