Read the info in the post "Williams 773" The Diode solution works great! I have done it with my Williams' Steamers with wonderful results. Very simple to make and wire into the motor circuit. The scale Hudson has the motor control board within the tender. You add your diodes there at one of the two wires leaving the board which connect to the motor via the "tether". Look at the Dallee circuit that Joe Satnik has put a link on to his part of the 773 post
Hope this helps...671
Hope this helps...671