And if you cruise to a stop in the middle of a train crossing?

Or if the steering shuts down while on a long curve next to a cliff?

Trains travel slower through populated areas. If you're stuck on a crossing jump out. Chances are the train will stop if the driver sees you in time and has the distance to stop (about 1mi/1.6km).

Steering doesn't shut down, it just goes from easy to hard. If the car is in motion it requires very little energy to turn.