So I hooked up the 180 brick to the track and disconnected the ZW-L. Tried the GG-1 and it worked perfectly. I then tried the GP9s. Also worked perfectly. I even tried running the GPs and the GG-1 all at the same time. The 180 brick performed fine and no tripped breaker.
I then tried the GG-1 by itself powered by the ZW-L (set at 18 volts). The ZW-L flashed the red light.