First off: Welcome to the zoo!! (We're all a bit crazy, but you'll get used to us!) You may want to stop by the Welcome section and tell us a bit about yourself.
I don't know why some manufacturers put a non operating coupler on one end of a product. Cost, I guess. I don't know anything about the Trackmobile, so I can't help too much with specifics. I would recommend that you look at all Kadee's couplers and see if there's one that you could graft onto it. You may have to get a bit "creative" and mix and match gear box with couplers. That's probably what I'll end up doing to a Mantua 4-6-2 Pacific I have.
One other loco that comes to mind that is the same way is Bachmann's 0-6-0 steamer. Operating coupler on the back, molded on plastic dummy coupler on the front. ON A SWITCH ENGINE!!
But....... I've figured out a way to get an operating Kadee on the front and it matches perfectly with the height gauge! I'm going to write up a "HowIdunnit" article on that and post it here. So just remember, we're all pulling for you!
Thanks for the welcome I will visit the welcome section
Thanks for the advice. the coupler is "molded" into the metal body, I was thinking about cutting and drilling it out but.... Not sure - I wil post a picture