Cerys - Design

 This locomotive design has grown from the design of the tram engine. The basic chassis of that came from a 1983-vintage design called 'Geraldine'. This locomotive was designed to be a simple yet practical engineering project for ICI apprentices at Warrington. It features:

The above features make it robust: a good first project. I do not possess a lathe, so I shall be purchasing the wheels ready-turned. I shall be borrowing time on a lathe to turn the axles, but, other than this, I intend to do the rest of the construction in my workshop at home. This workshop has a good, solid bench, a vice, a drill press, various hand tools… and that's it. In other words, it's within the capabilities of most people. Indeed, as construction progresses, I intend to document it in words and pictures so that if anyone else wishes to do the same, they can do. Should you wish to do this, I suggest you read ALL the pages first, because I'm certain I'll find better ways of doing things as construction progresses. The usual disclaimers apply to this, of course…..

Cerys is intended to bear a passing resemblance to a slope-sided Ruston and Hornsby 11HP contractors locomotive. Thus, she features a transverse driving position, combined with a small size. This is ideal for up-and-down tracks, where visibility of the entire track is required.

Below is a (rough) isometric view of the design. The cab back and seat are reversible, to allow the driver's feet to protrude either side. For this reason, there is also a step on both sides of the engine. The driver sitting on the locomotive adds considerably to the adhesive weight of the locomotive: however, the axles needed careful positioning to ensure that it remains stable. Thus, the rear axle is further back than aesthetics might dictate.

The petrol engine sits under the bonnet, and the transmission will be under the driver's seat. This drives a layshaft between the wheels, which then drives down on to the wheels. The engine to transmission link will be by belt, the rest of the transmission by roller chain.

She is built to metric dimensions: Not because I have any particular feelings in the metric/imperial debate, but because supplies are much simpler to obtain in metric. Almost all bolts/nuts are M6 for simplicity.

Principal dimensions are:


41" (1030mm)


24" (600mm)


20" (500mm)

Wheel diameter

6" (150mm)


19" (480mm)


Click on the any of the following hyperlinks to view the design drawings:

General arrangement - side view

General arrangement - front view

General arrangement - plan view