colour light signal

Definitions

An electric railway signal with colour aspects, showing either red or green in a 2-aspect signal, with the addition of a yellow or double yellow aspect (meaning caution) in 3- and 4-aspect signals.

UK

Equivalents

Examples

“Colour-light signals, for both day and night work⟳, came into use⟳ at a much later date⟳, and their first use⟳ on any scale in this country was on the London underground railways, where the principle adopted was largely American in origin. But although light⟳ signalling is credited to America, one of the first instances of its use⟳ was an experimental installation at Herne Hill, although it did not find⟳ favour in this country for overground working until some fifty years later.”

CEFR level