changing K-Line SW2 to d.c.

The switch most likely is a direction lock. Just wire the motors directly to the track,which is the pickup roller and outer rails. Remove the wires from the board or remove the board all together. There are systems that reverse standard E units back and forth,so you can make it work on AC with the existing E unit. You can also make your own system with relays and timers.

Dale H

Wally; Red and black wires are track pickups, red is center rail. Blue and yellow are motor wires. You need to disconnect everything and reconnect just the motor wires and the track pickups. Note that the blue and yellow wires are most likely cross wired: one yellow connected to a blue wire. the other pair connect to each other. This is because the two motors are mounted in opposite directions in the trucks. One motor faces right and the other faces left. They need to run in opposite directions so that they both move in the same direction going down the track. Wires to the headlight connect to track power as usual.