Not quite the same because they don't control as easily who drives on the roads. They can easily stop you from getting on the train though.

"They" routinely close or cordon off the roads & sections. They also suspend license privilege (obviously as allowed under laws & regulations).

This would be no different than cancelling the whole train or train route; & stopping or cancelling one's entrance pass to train station.

If the government ceased to exist, the roads would still exist. I doubt the train would continue to run

The roads would continue to exist in a road usable by modern cars for only about 10-15 years. Have you been to any failed state? :-)