Signalling has always been digital. Signals were referred to as either Off for go or On for stop. With points either Normal or Reverse. The levers are like on/off switches with the software being the locking under the frame all done mechanically. The only analogue bit would be adjusting the wire lengths, throw for points and the brightness of the oil lights used for the signals.
Posts by jets69
4 publicly visible posts • joined 2 Mar 2012