madmax,
If you want to run your modern engines Lionel or DCS/P2 with the ZW or KW, simply put a Scott type, 10 Amp resettable breaker between the old ZW or KW and the TIU. If you do not have a DCS or Legacy, definitely look into them, they open up the remote control train world for you & the kids. The breakers keep the ZW from damaging the Lionel or MTH P2 engines and the TIU. Many people use the quick blowing fuses instead of the breakers, I like the Breakers because they are resettable, after turning the power off.
I run all my old and new Tin Plate trains with the DCS hand held remote control, the old stuff runs smooth as silk using the DCS.
Junk the CW-80 or use it for an independent street car line.
PCRR/Dave