I could use some help. We have built a nice modular three rail layout for the community at the local arts center and are running locos conventionally. I brought a fairly new MTH PS-3 switcher today and, though there was power to the tracks, it did not run. We were using a twin transformer I did not recognize and I don't know how much power was sent to the tracks. It was running other three rail locos fine. There is no conventional switch on the PS-3 loco. Does anyone have a suggestion? Many thanks in advance.