found: Work cat.: Vanns, M.A. Signalboxes, 1997:p. 7 (a building containing equipment to alter and control route setting and aspects of fixed signals to be observed and reponded to by train drivers, and the means to communicate between other buildings so equipped, and with train drivers, to co-ordinate the movements of trains along sections of line)
found: Web. 3(Signal tower: an enclosed or armored elevated structure from which signals are displayed or controlled; specif.: a switch tower for a system of railroad signals. Signal box in Brit: Signal tower)
found: OED(Signal, n 5b: Signal box)
notfound: Jackson, A. A. The railway dictionary, 1996
