Electrical Changes

Making the mainline 1 big loop required some wiring changes. The leads from the rotary switch powering the line from the port to OBrien had to be swapped green for orange. This made the positive and negative tracks the same from the port to Grants Pass. O'Brien is still powered by a DPDT switch but the power leads to the coal mine had to be unhooked from that block.The port was gapped making it electrically separate from the rest of the railroad.  The black and red feeders from Waldo were joined to the blue and white feeders of the mainline, at the terminal at the end of the port. The old Waldo rotary switch was used to power the green and orange feeders powering the track now designated as the Northern Pacific. These feeder wires were also reversed at the terminal to keep the correct rail positive. At  Grants Pass the blue and white feeders, from the DPDT switch, had to be swapped blue for white, at the terminal there. The turntable at the port was also powered. This divides the layout into 4 blocks. The port, the port to O'Brien, O'Brien to Grants Pass, including the Waldo branch, and the N.P. connector. Power to Grants Pass and O'Brien is selected by throwing a DPDT switch to 1 of the 2 connecting tracks power. However the DPDT switch powering Grants Pass when thrown from N.P. to the mainline or vice-versa will also change the engines direction, as this is the 2 tails of a loop, joining in Grants Pass although it is not meant to run as a loop. This is caused because of the need for a crossover near the ports turntable that joins the N.P. Track to the port track.
This post is mainly for my reference.