1851 Great Exhibition: Official Catalogue: Class V.: Stevens and Sons
609. STEVENS and SON, Darlington Works, Southmark Bridge Road — Manufacturers, Proprietors, and Patentees.
Model of railway junction semaphore signals. The platform is raised from the ground from four to eight feet, to afford the signal-man a good view of the line. The two signal-posts represent the meeting lines of railway. The arms and lamps are worked by the foot of the signal-man, leaving his hands at full liberty to pull over the switches or shifting rails; on the removal of his foot from the stirrup and his hand from the switch lever, the signals readjust themselves, the arms standing out at right angles, and the lamps "red," stopping both lines.
Model of a double station signal, provided with an arm and lamp working simultaneously on each side of the post, to command both lines by moving either of the hand levers.