How long can a Railroad switching an industry block a road crossing?

Here in California it depends on the situation. If the train is moving there is no specific time, just however long it takes for the train to pass. It is only supposed to be able block a crossing for five minutes if it is sitting still, but they have only to move and the time starts over so it is not very meaningful. If a train breaks down or is in an emergency situation then it can't move until the problem is gone.