This Midland Railway brass plate was fitted directly behind the levers on the top of the tread plate and described the levers function to the signalman. The plate is engraved and retains much if its hard wax infill. Black wax was used to indicate points,facing point locks and bars. Red wax was used to indicate the lever operated a signal or ground signal. The plate measures 127mm X 102mm X 3mm.
This example has the much earlier larger font and has a fantastic description with "2nd" which is rare wording. The operating lever controlled a signal so infill is in red wax.