deadman's brake

plural deadman's brakes · alternative dead man's brake

1. A brake that normally operates under pressure, but engages fully when all pressure is released.

   1 more example

   Two rates of deadman's brake application are provided on the locomotive to suit the class of train being hauled. Selection is by the Braked/Unbraked changeover switch. This does not affect driver-controlled braking, but allows a slower rate of application of the deadman's brake when hauling unbraked stock.

   1960 February 28, “High-Voltage Electric Locomotive for British Railways”, in Railway Magazine, page 125