I'm really interested in where you got that worm gear! I have one of these that I had Frank Timko fit a larger motor to. However, I have the one that I did all the work to upgrade it to TMCC with the Super-Chuffer, fan driven smoke, etc., and I'd love to stick a larger motor in that one as well. The mounting plate looks very professional, you obviously have a mill of some kind to do that work.
I looked around, where exactly did you get that motor? What is the exact part number? I looked at a bunch of them on eBay and AliExpress, but they didn't seem to fit with the operating requirements of the locomotive.