When computers fail here in the Netherlands, trains are just stopped until they can be fixed.
In some cases, trains can be ordered to drive "at sight" -- slow enough (walking speed, basically) to stop if there's something visible on the tracks that shouldn't be there (train, car, person, cow, whatever)
In some cases, trains can be ordered to drive "at sight" -- slow enough (walking speed, basically) to stop if there's something visible on the tracks that shouldn't be there (train, car, person, cow, whatever)