trainstop

Noun

train stop (plural train stops)

1. A train protection device that automatically stops a train if it attempts to pass a signal when the signal aspect and operating rules prohibit such movement, or (in some applications) if it attempts to pass at an excessive speed.
   • In the simpler operating conditions of the London Transport lines, plain automatic train stops, applying the brake if a red indication is passed, give all that is required. With improvements in design, they have been in use over half-a-century.1957 July, T. S. Lascelles, “British Signalling Developments since 1897”, in Railway Magazine, page 467