colour light
noun1
Rail transport, Railways, Transport UK, Abbreviation Short for colour light signal.
- Progress cannot be denied and must not be deprecated. Colour-lights are obviously the signals of the future. […] The traditional British signal is on its way out. Unsentimental officials will doubtless decree colour-lights from Kings Cross to Waverley, and from Paddington to Penzance, with upper quadrants on minor branches.1957 June 23, S. C. Crowther-Smith, “Lower Quadrant”, in Railway Magazine, pages 422, 423: