Hi Kevin, Do you mean a PWR-56? This power supply uses awg-16 wire directly to the track. THe PA-2 module comes from 120v to the PWR-56 with a single plug in wire which is supposed to be supplied.
http://ringengineering.com/
Check our user site, it has a lot of info about RailPRo http://rpug.pdc.ca/
The other Mel