THE MIDLAND RAILWAY ASSEMBLAGE TRAILS
"The Family Trail"
Stop Fourteen: The Lever Frame

Time to turn around again and walk back toward where you started — have a good look in all the drawers though. The Metal area continues all along this aisle.

Stop 14

Where: B16 (end of the aisle)

What: A Victorian computer (sort of)

Material: Steel

Why: It may not look like a computer, but the signal lever frame does in fact apply the same IF (condition)… THEN (action)… logic as computer code. Pulling the levers (sorry, unfortunately you can’t here — too many moving bits to trap unwary fingers 🤕) would operate signals and points. The signals should only be cleared when the points are set correctly though, otherwise a collision can happen. To make sure the signalman didn’t forgetfully pull the wrong lever and cause disaster, a system of mechanical interlocking at the back of the frame applied the “logic”. Though this example is a very simple frame, the interlocking could be incredibly complex, sometimes with over 100 levers involved, This really is Victorian ingenuity at its finest and lever frames like this still control trains today (and in some surprisingly busy places).

Ref: 88-OBJ/003

Page last updated: Sunday, 30 January 2022