Preece's-type telegraph block instrument
Telegraph block instrument; Preece's type; block section release instrument with combind bell. Absolute single-semaphore (lower-quadrant/red with white spot) block-indicator 2-position/2-indication (Line Blocked/Line Clear), mounted on a vertical brass-finialled post in a large circular brass bezel. Beneath this is an enamel-plate inscribed "Up Line". A bell-dome and striker is mounted in the recessed top of the instrument, below which an extra signal-indication in a semi-circular aperture has been blanked off. A Preece "Off/On" switch-handle commutator and a Preece bell-plunger would accompany this instrument when in service.