I've just stumbled upon a variation on a crash-bug I discovered and wrote about years ago. I've known for a while that if you pause the game while an engine is in a station, about to put on a bunch of cars, then deleting the track it rode in on will see those new cars placed on dirt. As soon as time rolls, the cars won't, and the game crashes.
My variation is to pause the game, replace a bunch of engines, and then adjust the path of some track. When a train's engine is replaced, the train becomes a ghost with the cars in limbo. The game will allow a player to delete the track right under