Hi Rob,
Glad to hear you survived the train. I have been a fire fighter for 25 years as a volunteer and full time. I have been to hundreds of car accidents and only a few involving a train. I have yet to see somebody beat the train and survive. You have an angel watching over you.
As for cutting the battery cables, in the Ottawa are we usually loosen the bolt and take them off properly unless the car is right off.
Stay safe.
Cheers,
Greg