The signalman inside Salisbury West box operates the slides that

in turn actuate the signals and pointwork. The electro-pneumatic system was an experiment by the L&SWR that was tried at a number of other locations on their network but was one that was not widely adopted. This system of signalling in the Salisbury area had just a week left in operation from when this photograph was taken to be replaced by conventional multi-aspect colour lights operated from a panel installed on the station's platform two.