08-26-2009, 07:08 PM
Building a spring loaded pin that raises between the rails when the liftout is removed will keep you from backing a train into the abyss. I built a pair for a friends layout that would retract, when the weight of the liftout was on them, out of some flying model airplane control parts, a spring, a pushbutton switch (normally open), a screw and some brass stock. I think I got the springs from a hardware store, the push buttons from Radio Shack and the brass and model airplane control parts from a hobby shop. The rod was a piece of metal pushrod that threaded into a metal clevis (Du Bro or Sig IIRC) and this in turn pivoted in a hole drilled in the brass strip. One end of the brass had a hole drilled in it so that it would pivot on a screw that was run into a piece of the benchwork. The spring would push the bar up when the weight of the liftout was removed releasing the push button to open the track power circuit and raising the rod to stop any wayward trains headed for the gap. Worked like a charm with only about an hour of work to fit the pieces together, drill the holes in the roadbed, put them in place and add the wires so the cut-out would turn off the power to the approach and do some final tweaking to make it work without binding.