Technic
Scale Models

These models are scaled for the Lego Technic figures or about 1:20. At this scale, the Lego train track is about 75cm (30inches) gauge.

Lego trains are very limited in terms of wheels: there is one kind of car wheel and one kind of motor "block". I decided to experiment with various model train wheels and axles to see if I could use them in 1:20 scale models. There two problems with this approach: the wheel profile has to be compatible with Lego's track geometry (including switches and crossings) and the gauge has to be right. G scale wheels have the right profile, but the gauge is too wide. I found that it was possible to adjust the gauge of LGB and Bachman axles, just by carefully pushing one wheel inward on its axle. The axle is then cut to length.

Both LGB and Bachman axles are just the right diameter to slide on a Technic gear (although some glue would probably be needed if a high torque application is desired).

My first attempt resulted in this green industrial locomotive (critter) which is powered by a Technic motor with the power beeing fed through a cable for now. I intend to develop some kind of wiper so the locomotive can be track powered.

Using regular, double flanged, Lego wheels, I built the following "18inch" gauge engines and car. The engines are powered by micro motors (although the back one's was removed at the time of the picture). The black engine includes an on board battery, which is prototypical for a mine locomotive. The "red" locmotive was built at a time when I had a lot of other models built and parts were scarse...

Here is a Lego copy of Bachmann G Scale Shay locomotive. It is made of a mix of Technic and regular Lego parts (I ordered several bulk brick packs in order to complete it.). I wanted to build such a locomotive for quite a while, but I couldn't figure out a way to reproduce the Shay's telescoping shafts. While building the super car, I noticed that the parts used for the rear view mirrors would fit my needs. The problem was that there were only two of these parts in the super car, and I was not ready to buy a second one, just to get those two parts! So I looked through Lego's web site and found one small ($6) motorcycle kit that had two of these parts. Obviously, the only parts I couln'd copy in Lego were the wheels: some day, I will get around to modify G scale wheels to mount them on Lego axles.

This picture shows a conveyor belt that I hope to combine with some of the 1:20 scale trains and other equipment into a mining diorama.

Here are a couple of trucks I built. I had the pleasure to build the super car (set #8448), which I kept for a couple of weeks and then took appart and turned into the truck shown below.

This truck has a four wheel drive with two differencials (the second one was borrowed from the RIS): next time I build a four wheel drive vehicle, I'll add a third differencial, so going over steep bumps and steps is not a problem! As you can see from the pictures, the truck has a central articulation as a mean of steering. My original intent was to build a motorized steering using a rotary encoder for position feedback... It obviously did not happen! I put the super car's V8 engine in the spot originaly reserved for the RCX.

Although it looks pretty nice (check out the papillon doors!), this truck was a bit of a desapointment: there was not enough gear reduction for the traction motor, so the truck could barely move... Of course I never got around to program the RCX to control the steering...