sand drag

noun1

1. •
   (UK) A pile of sand or earth at the end of a siding or bay platform, intended to stop trains that overrun or pass through trap points set for a siding.

   • The brakes were applied immediately, but the engine ran into a sand drag at approximately 20 m.p.h., plunged down the embankment, and turned over on its side at the bottom. — 1952