dead manβs handle
n.β Β«In the motormanβs cab there are two levers, a braking lever operated by the right hand and the controller lever, equivalent to an accelerator, which is operated by the left hand. The controller is also called the “dead manβs handleβ” because it must constantly be pressed downward against a spring to accelerate the train. When the motormanβs hand is lifted from the lever, the lever springs upward and the train automatically brakes.
Β» ββBrakes Were Off On Subway Train Involved In Crash” by Edward A. Gargan New York Times July 6, 1981. (source: Double-Tongued Dictionary)