The impossibilities of this actual event occurring are incredible. Good thing it is fiction since this type of event couldn't happen thanks to the installed air brake fail-safes on every train in use since 1870. When a train loses air pressure in its braking system it causes the brakes on each car to lock up successively, spreading from the initial problem and moving towards the front and rear of the train. Emergency brakes are actuated on a train by a LOSS of air pressure NOT an existence of one. Similar to the way the air brakes work on a semi-truck...
"Anything that causes a QUICK drop in brake pipe pressure at any car, will trigger that car which in turn triggers adjoining cars and thus puts the whole train in emergency. This initial trigger could be the engineer, the conductor pulling his emergency valve in the caboose, the brakeman pulling his valve in the cab, the train or air hoses coming uncoupled, or an air hose bursting."
The producers should have discussed this movie with a REAL train person before they created this farce. This movie isn't worth watching past the first half hour if you are looking for any bit of a credible storyline.
"Anything that causes a QUICK drop in brake pipe pressure at any car, will trigger that car which in turn triggers adjoining cars and thus puts the whole train in emergency. This initial trigger could be the engineer, the conductor pulling his emergency valve in the caboose, the brakeman pulling his valve in the cab, the train or air hoses coming uncoupled, or an air hose bursting."
The producers should have discussed this movie with a REAL train person before they created this farce. This movie isn't worth watching past the first half hour if you are looking for any bit of a credible storyline.