Locomotive Speed Limiter (LSL)
The Locomotive Speed Limiter (LSL) is a system for controlling brake applications on locomotives operating under Automatic Train Control (ATC). By controlling brake application rate, LSL reduces the risk of derailments due to high buff forces caused by aggressive penalty braking, while still permitting the train to stop within a safe distance. LSL is required on Amtrak-owned trackage, such as in the Northeast Corridor.