Reply to "wiring diagram for american flyer e unit S gauge and O"

those prewar units are tough.  The wires are very stiff and can easily flex the finger away from drum contact.  1st make sure you clean the fingers and drum and then make sure they are installed correctly and sequence each time properly.  You should also check those wires, they are notorious for looking good on the outside cloth insulation  but dissentigrating on the inner plastic  part and then shorting through the cloth where they pass tight corners etc.  This one provided an immense amount of fun......