Traction Engine with Power Functions

Welcome to a bygone age, a glorious time of steam engines and new industries. This is a working model of a steam powered traction engine, complete with the flickering glow of a coal powered firebox and the chuffing motion of a steam cylinder as it turns steam energy into forwards momentum.

I recently visited a heritage railway near Bristol here in the UK and found that there was a great love for all things Lego and all things steam powered. I built this model traction engine for that day trip and shared it with several families who had come to see the steam trains, many of whom even took my little tractor for a drive down the platform.

I have used standard technic parts and created the tubular boiler shape by placing beams around a wheel rim. The steering mechanism is as authentic as I could make it with Lego pieces and the firebox flickers thanks to an oscillating Power Functions switch hidden in the superstructure, switching a set of Power Functions lights.

The main drive comes from a Power Functions XL motor, which also drives the firebox switch. Steering is activated using a Power Functions M motor and this is all controlled using either a Lego Trains controller or a standard Power Functions controller.

I have simplified the steam piston on the top so that it can be seen to work, while still spinning the fly wheel, but this is all driven from the XL motor hidden in the chassis. The battery box is placed on the back of the tractor and can be very easily replaced when the batteries need changing. The power leads are all hidden inside the model and are routed to avoid clashing with the drive system.

An alternative version could easily be built that does not have drive motors, but it would also lack the flickering of the fire box. With Power Functions systems in place, this is still a build that can be tackled by younger builders and the mechanisms used in this model encourage these builders to develop new techniques and ways of thinking about building their own models.

The tractor is also powerful enough that it can pull a trailer should one be wanted. I have geared the drive system to make it relatively slow in its movements, but this does not detract from the fun element of driving the model indoors and outside.