metal tape under roadbed vs crisscross wire for TMCC ground

The ground wire in your home (also the pin #5 on the serial connector on the base) carries the airborne TMCC signal to the top of the engine. If there is a track over the engine on a track below, the track over will block that signal from the air to the engine below. You just need to run a ground wire over that track below. It does not have to be tape...just a skinny wire. Do not run it right under the track above, but a couple of inches, if possible,  below the track above but still above the engine on the track below. Or even to the side somewhat of the engine below. In the case of a metal tunnel, same problem. Run a ground wire under the roof of the tunnel. That's all it's about. Make sure the top of the engine can see the ground wires in your house, or the ground wire you suspend over the engine.