Shamus. I have figured out the wiring, and would you believe it works great.
the DPDT toggle, you wire one center post one to the positive and the other to the negative side of the power supply. One of the end post goes to the common rail and the other to the rheostat. You wire the SPST toggles center post to individual block on the lay out, and the right side of each SPST toggle goes to the right rheostat for Cab A, and the left side to the left rheostat for Cab B. Believe me it works, I want to thank you for all your help.
I have one questions, Do you know an e-mail address of a good company who sells wiring, I need to get SPST toggles and a rheostats. Again thank you for all your help