Installing a Digitrax DZ123 in Thomas the Tank Engine

Thomas is a small 0-6-0 steam engine made by Tomix for UK 1:148 scale n-gauge railways.
I run Thomas, Henry and James at the Christmas Zoolights at the Oregon Zoo in Portland, where the Thomas trains are very popular with the children! thomastrains.jpg

There are apparently now three different versions of the Tomix Thomas, and I have seen all variants, with different internal design. This example has the motor extending into the coal bunker at the rear, but leaving space in the top of the cab. Another version has a taller motor, and a small weight in the bunker.

Preparing to Install

Thomas body removed

The body shell is clipped on at front and back, but lifts off pretty easily.
The power pickups in this engine are on top of the wheels, and collect dirt very well as the wheels turn! Cleaning under the pickups is required frequently if the track is at all dirty.
The power feeds to the motor are easily visible here, and have to be disconnected as the first step. A very brief touch with the soldering iron while applying a little pressure or leverage with a small needle-nose pliers will do it.

Thomas decoder wired

Wiring this decoder requires separating the power from the motor, and then connecting the 4 power wires.
The decoder is going to sit right above the motor, and so the red, black, orange and grey wires can be cut to length before attaching. A little slack makes it easy to remove the shell again later.
I cut all the wires to the same length, anc coiled the unused lighting wires close to the decoder, in case I get around to installing lights later.

Thomas decoder wired and taped

The contacts need to stay separated, and I used a small square of electrical tape each side. Shrink sleeve could also be used, but restricts the flexibility of the wires somewhat.
The decoder is going to sit right above the motor up in the cab, and I covered the bright Digitrax red with black electrical tape.

Thomas decoder in place in the cab

The body shell then clips back and Thomas is ready to roll!



Questions or more, please contact me.

All site content and photographs Copyright © BBM Group LLC & Bill Chown, 2003-2009.

This page last updated BBM