When the engineer makes an automatic brake application, the locomotives apply too unless the engineer bails them off by pressing down on the independent brake handle. Bailing off keeps the heavy locomotives from stopping faster than the cars behind them, which would run the slack in hard, and it keeps locomotive wheels from overheating on long grades. Rookie engineers who forget to bail off feel the whole train shove into the head end.
Bail off the units on that set, we've got a hundred loads behind us and I don't want the slack running in.
Also heard as
- actuate
- bail them off
Related terms
Slack
The free play in couplers and draft gear that lets cars move a little toward or away from each other.
Dynamic braking
Retarding force made by turning a locomotive's traction motors into generators and burning the energy off as heat.
Set and release
Applying the train's air brakes and then releasing them, the basic sequence of every air brake test.
Brake pipe
The air line running the full length of a train that charges and controls every car's brakes.