GWR Route: Banbury to Wolverhampton

GWR Route: North Warwickshire Line

Birmingham Snow Hill Station: gwrbsh1743

An electrically operated double dwarf ground signal at the north end of Snow Hill station. The cover has been removed to show the internal workings. At the bottom is the electric motor, which drives a vertical shaft with two sections of worm gearing. Depending upon the magnetic clutch operation the vertical shaft will operate the two signal arm shafts. These shafts connect directly to the signal arms outside the box. There is a magnetic clutch for each signal arm shaft and on each shaft behind the clutches are a number of position indicator contacts. The box also contains two electric lights which can shine through either red or white lenses depending upon the signal positions. When installed the arms on these dwarf ground signals replicated the short independent ground signal semaphore arms already in usage on the Great Western Railway, but being at ground level they soon became dirty and the signal position became difficult to see. As a result around 1915 a decision was made to replace all ground signal semaphore arms with white enamel discs with a red bar. The enamel presented a smooth surface, which was much easier to keep clean.

Robert Ferris

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