Great Western Railway Tubular Steel Type Signal Assembly from High Wycombe, West Ruislip, Gerrards Cross & West Ealing Stores

This gantry represents the signals placed at Northolt Junction (near South Ruislip station) which opened in 1908 on the Great Western Railway. The signals controlled the approaches to the junction where the line for London Paddington divided from the line to London Marylebone.

The red signals show ‘stop’ when horizontal and ‘go’ when down (lower quadrant). The yellow distant signals provide a driver with a warning of what the next signal is showing, allowing him to slow down if necessary. Signal backs are painted white with a black band.

The gantry’s walkway and ladders provided access for maintenance and to top up the oil lamps which illuminated the signal lenses. Oil lamps burn with a yellow flame and blue lenses were used for the signals, because of the fact that yellow mixed with blue makes green.

These Great Western Railway lower quadrant pattern signals which move down to show green/go work in the opposite way to most mechanical railway signals, which are upper quadrant and move up to show green/go.