I have a set of F7A and B units with DCC installed in both. When I put them both on the track, how are they supposed to run together? Do I have to flip back and forth on the throttle and set them to the same speed or is there something I'm supposed to do? The A unit doesn't really move much if the B unit isn't also running. It also becomes a problem if when I want to adjust the speed or stop the train because both would need to be controlled at the same time.