John:
Basically all you need to do this is create a section of insulated outside rail. I'm assuming you are using tinplate track, so for a crossing, you'd probably want a minimum of 4 straight sections to be insulated. Take the sections of track you wish to insulate and carefully bend the tabs on the tie holding the rail in place so you can free the rail from the ties. To insulate the rail from the ties, use the same type of fiber insulator that is used to insulate the middle rail from the ties. I've tried using electrical tape in the past and inevitably it fails. Better to use the right thing at the start and avoid problems later. Slide these insulators onto the outside rail, spacing them so they will each be on a tie. Insert the insulated rail into the tie tabs and gently press them back down, securing the track to the tie. You can keep the steel track pins in the insulated outside rail between the sections of track that make up your insulated section. At either end of this multi-piece insulated track section, you must remove the steel pins and insert the plastic pins. Once you have done this, re-install the insulated section onto your layout.
Attach the power wire from your crossing gates or lights to the transformer. Attach the ground wire from the gates/lights to the insulated outside rail. When the wheels of your train hit the insulated section, they will complete the ground between your outside rails and activate the crossing gates/lights.
Curt
