Modelling a Moës diesel loco (2015)

Jan van Mourik

I was always attracted to small open-cab diesel locomotives, but building one in H0e scale (1:87) was nearly impossible until recently, due to the size of even the smallest motors. The current availability of small powerful motors however enables one to build such a model at last. Nigel Lawton amazed us all when he designed a working open cab O&K diesel in 009 (1:76) which he can be supply either built or as a kit. In addition, an open Simplex is available.

A friend recently gave me an N gauge 4-wheel chassis with a vertical motor by Caramel. The motor drives one axle over a worm. Because it has a tall motor it is rather difficult to build an O&K diesel, and due to the out-of-centre position of the motor a Simplex also is out of the question. However, a search on the Internet revealed the locomotives of the Belgian firm of Moës, from Waremme, who had several types in their catalogue featuring a rather tall engine compartment. I decided to build a model based on a Moës type AL. The model had to be semi-freelance due to measurements of the prototype being unavailable and having to work with the restrictions of the Caramel chassis.

Construction started by making up a simple frame, using two pieces of rail (for the solebars) and a piece of sheet brass. This was first fitted over the fixing lugs on the side of the chassis. The solebars however sat a bit too high for comfort.

After some filing and bending of the chassis bars it proved possible to press it further down so it fitted below the chassis lugs. This looked rather better.

Following this, the space between the solebars was filled with a piece of 1mm styrene. This was fixed with contact glue and secured the frames to the Caramel chassis. I then used the side view of photo 2 above as a starting point for some 'computer-aided design'. Using the Paint drawing package I drew the engine compartment and the open cab around the chassis and frames (see diagram).

As the chassis is fitted with two LEDs, one of which lights up according to the direction of travel, I decided to try and use this feature and fit lights to the locomotive. The problem here is that the LEDs shine up instead of ahead and astern. For the rear light I made a rather complicated light guide that in the end failed miserably. The headlight is better, but still rather faint in daylight if the model is operated at scale speeds. I even managed to ruin the LED that should shine astern, which proved rather less robust than it looked!

The chassis comes with a few pieces of lead to be used as ballast. One of these I filed to the flanged shape shown in the sketch below. This was glued to the front of the motor with cyanoacrylate glue, and was intended to fit the superstructure to once it had been completed. Thus the motor might stay accessible for maintenance.

The rectangular footplate of the locomotive was made from of a piece of plastic card, which was cut out to accommodate the motor and another piece of lead over the rear wheels. The latter is hidden from view by a plastic sheet with an anti-slip pattern as seen on some kinds of sheet steel.

On the chassis a light guide was constructed for the rear light which I wrecked in the end as I mentioned above, so the least said about that, the better!

The front and rear of the engine compartment were also constructed from plastic card. They were made tall enough to clear the light guide and the circuit board and LEDs on top of the motor. The front and rear sheets were then fitted to the footplate.

To the inside of the front sheet I glued two plastic angle profiles to enable the entire footplate/engine compartment assembly to be slid over the ballast weight described earlier.

After trial fitting, the front and rear sheets were glued to the footplate. In the cab compartment I fitted control handles and pedals, a weighted brake lever, a gearbox and a driver's seat, all made of scrap plastic.

Following that, I made the two halves of the bonnet top to size, and after bending them they were glued to the front and rear sheets. The headlight is a piece of clear styrene with a brass rim, and the exhaust was made of the remains of a ball point pen, less ball. Both were glued to the bonnet.

The photo above also shows the lead sheet used to fill the sides of the engine compartment. On these I glued louvres.

The photo above shows all the detail before painting. The end result after painting and weathering is shown in the photos below.

Achieving better control of the Caramel N gauge chassis

The extremely high speed and inferior controllability of the Caramel chassis on a normal 0 to 12V power supply caused me to experiment with serial resistors to improve controllability. I tried several resistor values as follows:

I obtained a number of 150 and 162Ω resistors to be able to modify other Caramel chassis in future. As the calculated power consumption in the table shows, it is quite acceptable to use ¼ W resistors, especially as the loco runs only short distances on an end to end layout.

With a Dremel cutting disc I cut through the copper conductor layer on the circuit board in two places, at right angles.

At one end of the longest cut I drilled a 0.5mm hole to take the connection of the serial resistor. This is then bent over and soldered to the motor terminal. The other is bent back and soldered on the conductor strip.

Photo album