I am having a problem with the older Roco built S-2s. They stall on the Shinohara code 83 turnouts where all other engines including Roco built FP-7A units work fine. The pick up system looks ok but it seems if you wiggle the truck slightly the unit moves again. I am wondering if the back of the wheel is contacting something it shouldn't. The wheels and turnouts check OK with the NMRA gauge.
Any suggestions ?