The W&MR has separate cab-control panel, near the seats and drinks, and block-control panel, near the complex junction. Power supplies are indoors with a cable out the window, with an automotive 6-way connector.

here's the wiring diagram:
Wettington and Mahawatu Railway wiring diagram

Simple eh?

Heavy black lines are a shorthand for two wires (+ and -, or track 1 and track 2). grey means future wiring. The coloured lines are the track power zones
Red: inner loop
Yellow: outer loop
Green: Akatarawa branch
Blue: Thorndon branch
these colours are used to colour code wiring

Each zone can be connected to a cab using the Mahawatu panel. (The Wettington cab-control panel decides what two throttles drive each of the two logical cabs). Within each zone, the numbered blocks can be turned off by the Mahawatu panel to park up locos.

The hexagons at Puk Bay are remote control turnouts.

I use regular 2-core black garden lighting cable - I bought a whole drum. the main power feeders between the two control panels and from the indoor power supplies use 3-core mains-rated extension cord. 20m extension cords from China are so cheap that i cut the plugs off and use the wire.

there is only one feeder to each block. every single rail joint is soldered or has a soldered jumper wire across it. i may add redundant feeders to the other end of some blocks later.