The pedal must be depressed at all times except when the locomotive is stopped and 30 pounds or more brake cylinder pressure exists. If the pedal is released during operation, the safety control whistle will sound for two to four seconds during which time the pedal can be depressed preventing brake action. Otherwise a full service application of brakes will be made. Dynamic brake interlock is furnished with dynamic brake equipment and is used to release locomotive if the dynamic brake is on. Independent application and release of the locomotive brake is available at all times irrespective of dynamic brake operation.
Railroads specify conditions that operate the interlock.
The switch is reset automatically as soon as the brake pipe is recharged or main reservoir air pressure drops below 40 psi. Railroads specify conditions that operate the switch. At the engineman's control station, open control breaker and generator field switch leaving the engine control breaker closed. On some units equipped to MU with units of other manufacture, the control breaker must be left closed until control and engine control breakers are closed on unit being cut in. Insert automatic and independent brake valve handles.