Making Steam

There is a small, family-run company in Germany called Regner, which makes incredibly detailed, functional steam engines that are used in garden railways and model boats. The company has an extensive line of engines, and all are handmade to exacting specifications. After extensive measuring (and measuring again), I placed my order and waited six months for the engine to arrive. After opening the box, I poured over the manuals and did many test firings to break in my new toy. The unit is all one piece and includes the following: a compressed-gas fuel canister, a 320ml boiler assembly, a two-piston engine, a directional valve, an oiler, and a flywheel with driveshaft. Since the unit is self-contained, it made for easy mounting to the chassis. The driveshaft from the engine is mated to an Axial Wild Boar driveshaft, and that connected up perfectly to the transmission spur assembly via a 5mm output shaft that I grabbed from my parts bin. I am running a 12T 32p pinion to a 56T spur to get my final drive ratio. During the build, many people that saw it were concerned that this little engine was going to be a dangerous thing on the trail. Rest assured, there’s a safety valve installed that blows off excess pressure just like its full-size counterpart. As an aside, this unit produces about 33psi—about the same as a typical bicycle tire. Distilled water is the preferred water source as it reduces the risk of calcification inside the boiler. Of course, there’s an option for running a steam whistle, and plumbing the tubing for that was a fun process. Routing the pipe around and out underneath the body made for some head-scratching bends with my mini tube bender! Faithful to the full-size version, steam also puffs out from either side of the truck under the front wheel wells.