Doesn't feasible, but maybe there is a TMCC reception signal just because of the engines' antenna location (I know it is one of the metal handrails, but one could be on the left, other on the right). So, as a dumb check on my unfeasible idea, have you tried turning the Big Boy around and running in the opposite direction?
I also know that an earth ground laid next to a problem area can improve TMCC reception. So, at least to my mind, a quick check would be to get an extension cord that has the earth ground (three blade plug/receptacle), plug it into the same power strip as the TMCC command base, then lay the extension cord along the side of the switch. If this fixes your problem, you can come up with an esthetically pleasing solution.
