Manual Cylinder Release

It is not always desirable to have air in brake cylinders . On vehicles that sat unused sufficiently long, brake cylinder is at atmospheric pressure due to leaks in the system . However, on vehicles that were used more recently, brake cylinders could still be pressurized and have their brake shoes pressed against the wheels. In situations where brakes need to be released, but waiting for a motorized vehicle to pressurize the system first is undesirable, such as in certain shunting maneuvers, or after a complicated derailment , sometimes the best option is to release brakes by manually dumping the brake cylinder pressure.

Vehicles typically come equipped with a red handle, located somewhere on their exterior, which dumps brake cylinder pressure when pulled. Beware that if the handbrake is released, the brake shoes will immediately depress and the vehicle will roll freely under the gravity influence .