train derailed Options

[bobgfla]

hi again guys from bobgfla when i was runing a activity on mlt bradge line train was doing fine on main line near were the b and m branch comes out heading west doing 15 to 20 mph lower then speed limit i get activity ended car derailed . its not checked off on the set up and have not head this problem on outher activitys . is there some program to stop this from happing. ????