I butcher old Big Haulers abandoned tenders left by themselves at night on eBay. (Yes, I buy tenders and salvage the stock sound PCBs out of them.) I have another Shay that they work quite well on, I just can't seem to find a way to connect with the Shay I just got because whoever tried to convert it to Soundtraxx removed the original PCB.

I recently purchased a used 36-ton Shay. It was set up for a Soundtraxx DCC card. I don't use DCC so I was able to get everything back to analog except the original PCB for a sound card that resides in the tender is gone. I was able to match the lights up and everything works. I had one wire left over that I am assuming might connect to the contacts for the engine but I don't know how to ground it to complete the connection. Can anyone help?

I feel your pain. A little over a year ago I bought a "New" Shay and it ran about 40 feet and the rear truck fell apart. You can get the die cast trucks here: 

https://www.ebay.com/itm/144707130062?hash=item21b13792ce:g:h4wAAOSw0plioVNz&amdata=enc%3AAQAHAAAAoKRbF02r7hEdj8j4uHLm7C5hNvpFPAosu9r8ebbRu0iQedBjvii%2BnRA36Nct6OewRUDL2ub9EwmQdfEtJTJrsoCFScXDJFvhNP7WG%2F5A4r%2BVlhLueq8tR%2BoY9hAj3i%2BdW6oV1INO9byNB6PwoMiNkgh4lyt3rY5SwTKgB6WVUTBfJEZBMXYP%2FYRlPrILnfj5z89JQXgxHVOffB%2FKY0M3xSg%3D%7Ctkp%3ABk9SR7DRt_W_YQ

I think he has the lowest prices.