Telegraph block instrument, Spagnoletti
Telegraph block instrument; Spagnoletti; GWR (Brittan). "Up/Down Line" (behind the glass/ivorine) pegging/non-pegging 2-vane ("Down-Line" vane-assembly removed) 3-position/2-indication. Underneath this is the commutator-arrangement of 2 keys (white / red), 2-flaps ("Clearing Point Fouled/Train at Signal") and metal-rod slide (to hold down either key, when in depressed position).