This happened in Enola yard as well, but that was weird how it happened the car rolled out 5 track through CP Mary about a mile switched directions then back through Mary, through a switched that was lined for it, into the head end of 21J... No one was hurt but the jokes that were made when it was all over were awesome.
they do but it's applied by air- air leaks away, then no brakes. on tractor trailers, a 1200lb.spring holds the brakes on, until 60lbs. air pressure is applied.