Bob,
The Z4000 is 10 amps per handle at 5-22 volts. Additionally, it has 4 amp 14 volt, and 4 amp 10 volt accessory outputs.
Instruction from MTH are lacking
What you need is a copy of The DCS O Gauge Companion 2nd Edition!
Everything you need to know about DCS is all in MTH’s “The DCS O Gauge Companion 2nd Edition", available for purchase as an eBook or a printed book at MTH's web store!