To everyone who contributed a suggestion or idea,THANK YOU!!!! 
My MTH Dispatching Board is now repaired and operational!
LK: Thanks for telling me where the broken wire went. Your belt tensioner comment is spot on as well. Poorly designed, and poorly assembled. It took a bit to get mine free. It is better than it was, but that is not saying much. I did not disassemble the motor and gearbox. It was running slowly when I first tried it, but gradually freed itself and was running fairly well when I stopped for the night. Is Red-n-Tacky a suitable grease for these plastic gears?
Jetguy: The belt wants to wander off the idler roller, but cannot, because it is wider than the original belt, and there is not enough space for it to clear the roller. And I do have a spacer on the pin to the trolley to help keep the belt in place. What we need is a replacement roller design. I have an idea which should work, have no access to a 3D printer. If anyone has access to one and is willing to help us out, please contact me via email.
BTW, drilling the hole for the pin is a pain in the tush. I ruined the first hole as the rubber just did not stay put while I tried to drill it. I finally hit upon the idea of clamping it securely in a vise with flat metal jaws. This kept the rubber from wiggling. But I still could not drill a straight hole. The bit traveled out near the middle of the tooth. So I reversed the belt in the vise, and drilled from the other side: Same result. At this point I took an Exacto knife and cleared out the rubber in the middle. This left me with 2 rubber posts with holes. I put the pin in, and it stayed. Not a perfect solution, but it works, at least for now. I'm not worried about a damaged tooth or 2 weakening the belt. I found out mine has steel belting inside the rubber.
Chris
LVHR
