Military Train goes into EMERGENCY at 50MPH!

How long it takes to from 50 mph to 0 with a load of Armor. When something like this happens the train crew has a spare air hose in the cab to fix if reconnecting it does not fix it. The air hoses are designed to break apart at the slightest pull as a safety measure (in case the train ever breaks in two from a faulty coupler). Once the break happens and the reconnect occurs the locomotives have to recharge the air in the brake line to release the brakes.