Scale Models

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I built a Lego train that can run on HO scale track. Again, I had to compromise when it came to select wheels: only double flanges were available, so both engine and car weren't able to go through turnouts and crossings.

The engine is powered by a micro motor coupled to the rear axle by means of a rubber band. Power comes from the compact battery pack (it contains a single 9V battery). The 1:20 scale Shay is in the background.

After building the HO train, I was left with one micro motor (I bought two to build a micro robot), so I decided to build a micro truck. I found that a half size spacer can be used as a ream for some of the smalest tires used by Legoland cars. As shown, the truck has to be steered by hand, but I want to try to mount a magnet in front of the steering axle and then add some steel wire under road plates, to see if the truck will then steer around town on its own...

Here is yet another application of the micro motor: a minifig scale mobile crane.

The pictures below show it at an unfinished stage: the top of the crane body has yet to be added and some details are still missing as well. One motor is used to rotate the crane, the other one controls the main winch. Each has a 1:24 gear reduction, using a worm gear. The winch is way too slow, so I'm looking into ways to reduce the gear ratio (I'll probably swap the 24-tooth gear for an 8-tooth one).

To balance out the weight of the boom, I used a weight brick (available through Dacta). This brick is a 2x6 element filled with metal. It is mounted to look kind like a superlift attachment.

Another crane I built is based on Lego's monorail (not available anymore). The original monorail was an articulated vehicle made up of three parts. The central part was a short element that was motorized. On each side of it were a car with one truck at each end and a special ball and socket joint to the motor unit. One of the end cars carried a 9V battery.

As you can see from the pictures below, I've altered this setup by turning the motor unit into a locomotive and built a special, depressed center car to carry the crane. The battery is used as a counter weight, so the crane is pretty powerful: it can lift any monorail track section, including a switch. The crane can slide along the body of the car to extend its reach.

This is a rotary dumper for railroad cars. The car is unloaded by rotating it about three quarter of a turn. The dump is designed so that the axis of rotation goes through the car's coupler. Since Lego couplers are magnets, the car on the dump can be rotated while the rest of the train stays put and coupled.

Below the dump there is a structure made from angled Technic pieces. At the very bottom, there is a conveyor belt that moves the load out of the dump. This belt is very fast (connected directly to a geared motor which can rotate up to 450RpM): it needs to clear the hopper quickly to keep up with the dump.

Copyright 2000 David Wegmuller