Simple block control

Three sidings on the layout will have the option to cut their power. This is to allow me to park extra engines if I want to. I didn't bother to wire up those tracks for dual-power input (via SPDT switches). Instead, I simply heavy duty SPST toggles that I mounted on a metal outlet box blank cover plate and inside an inexpensive blue outlet box. I used 16g wire to make all the connections.

The control box is mounted under the layout right near the edge and it is a simple matter to reach underneath and feel for the switch to toggle. The wires exits the box and goes to a terminal block on the right. This allows me to easily relocate the box in the future if necessary, and also make troubleshooting easier. 

Only one track siding is currently laid, as the other two are waiting for me to move onto the left section of the layout. But, for the main joint between the two sections I have a larger terminal block and I ran wires from the toggle box to that. This is probably overkill for this layout, but I would rather be overly-neat than messy.

Up until about 25 years ago, this method was the "standard" way to wire up a layout for multi-train control except that two transformers would go to the toggle switches. Now, even three-rail trains have been taken over with Command Control systems. Oh well... such is progress.