My F7a loco has been working fine with my E-Z Command Center. It now does not respond - not even making sound. I have turned the controller off & on and no result.
Have you checked all the connections for loose wires and shorts?
Do other locomotives respond from the same controller?
Have you tried the F7a with another controller?
I do not have two dcc locos. I do have an easy app loco and it runs fine. So the track connections seem to be fine. I connected a non dcc controller and the loco light came on however it remained silent (no motor noise). I reattached the dcc controller and the loco worked for a few feet and then quit working. All of this makes ne think something in the dcc controller is loose or something in the loco is loose.
Perhaps you could test the loco and controller at a local hobby shop?