"Is this a misprint?" Yes, the wiring diagram does not compute. The copies were difficult to decipher. It took a while to find the Track C rectangle (upper left of track plan). Track C would be the down grade of Track D.
Track C had center rails insulated from D. For conventional continuous running the C dial would be set at a lower voltage than D. Correct the wiring diagram to connect the C outside rails to U/common the same as the D outside rails.
That track plan and wiring diagram should have more extensive instructions.
