Abstract: A penalty brake application nullification-prevention system for a railroad train in which a bypass circuit is arranged in one embodiment to vent control pressure from the brake pipe cut-off valve of the locomotive brake valve, in order to prevent the engineman form improperly cutting out the brake valve to nullify a penalty brake application, by operating the brake valve cut-out selector valve. In this arrangement, the bypass circuit operates in response to operation of the penalty application valve when an unsafe operating condition of the train arises. In another embodiment, the bypass circuit is arranged to vent brake pipe pressure in parallel with the brake valve, so that, in the event the brake valve cut-out selector valve is improperly operated to nullify a penalty brake application, the penalty application will be initiated by a brake pipe reduction via the bypass circuit.

Abstract: This invention relates to locomotive brake control apparatus operable responsively to a reduction of the pressure in a train brake pipe as a result of train separation at a location in the train remote from the locomotive to cause cut off of the locomotive power supply, cut out of dynamic brakes, sanding of the rails, and a service brake application on the entire train.