Single-line instrument (sending/receiving)
Telegraph block instrument; GWR. Sending/receiving Single-Line instrument: 2-vane, 3-position/2-indication (Train On Line/Line Clear). Brass-plated "WEST TUNNEL BOX", with 4 large, brass, vertically-mounted slide-bar handles with catches. Above these is a long brass plate which reads "Receive /Release/Line Clear/Train On Line/Send Release". Ex Quakers Yard High - Level SB.