After a period of minimal modelling activity, juxtaposed with maximum procrastination, I have finally decided on and begun a new project. A recent edition of Narrow Gauge Downunder had a plan of a two-plank, narrow gauge ore wagon in 7mm scale (1:43.5). This looked like a challenging entry to O-scale, but why take on a challenge when one can complicate it by using a 1:43.5 scale plan to build a 1:48 (1/4″ scale) model?? I could have reduced the plan by 10% on our previous (now defunct) photocopier, but its replacement doesn’t do such tricks. So, the first task was to make a list of the reduced dimensions for all of the wagon’s components. Why not just make a 7mm scale model? The answer has two parts. First, I don’t have a lot of space, so using the smaller scale will allow other compromises, such as smaller radius curves and smaller structures. Second, my one On30 loco is 1:48 scale.
How can O-scale be both 1:43.5 and 1:48? HO stands for half-O, so O-scale must be 7mm to the foot, right? Not quite – as with HO (3.5mm) vs OO (4mm), it’s an historical issue. British rolling stock and loading gauge was smaller than on the European and US systems, so to make commercial models of similar size and thus able to use available motors and mechanisms, UK models were made to a larger scale. Plus, US manufacturers/modellers use imperial measurements, so their O-scale is 1/4″ to the foot (1:48). … Yeah, whatever. Let’s get modelling.
I began with the side doors and ends. There are two hinged doors on each side. The lower plank is wider than the upper plank. Initially, I scribed the gap between the planks onto .030″ styrene sheet, but I wasn’t satisfied with the result. So, I cut separate ‘planks’ from .010″ sheet and glued these to the .030″ pieces. I’m happier with this arrangement for the outside faces of the doors and ends, but will rely on the scribed line on the inside faces. I dragged a razor saw blade along both faces of each door to create a timber grain effect.

Next, I fabricated hinged straps from .010″ styrene strip. The hinge is represented by a piece of .020″ styrene rod glued across the strip. I mass-produced these by gluing lengths of styrene strip to a length of .020″ rod, then separated them once the glue had dried. Each strap was glued in place on the doors and holes for fasteners were drilled using a little jig.


I used HO-scale Nut-Bolt-Washer (NBW) castings for the bracket fasteners, but they look too large. Perhaps it’s an illusion produced by the dark/light contrast. Perhaps a coat of paint will improve the appearance. I cut the cast stems to be just proud of the inside face.

As with the sides, I initially scribed a piece of .030″ styrene sheet to represent the floor boards. I wasn’t satisfied with the appearance so, again, cut .010″ strip ‘planks’ and glued these to a .030″ sub-floor. Next, I added solebars of .040 x .080″ styrene along the floor edges. Then, I slotted those and the centre pillars to create strong half-joints for these critical components. It was then time to complete detailing the sides. This included the latches to secure the doors to the centre pillars and wagon ends. On the prototype, the latches are part of the metal strapping. While I was working up the courage to fabricate and fit styrene latches, I hit on the idea of modifying Keiran Ryan’s HO etched brass astragals as strapping and latches. The latches on the ends use complete astragals with one end folded at 90 degrees to accept a length of .020″ phosphor-bronze wire. At the inboard end, the wire is bent at right angles and passed through the hole in the astragal and the styrene end. On the sides, astragals were shortened to fit between the doors and their relevant latch bolts.



I depicted floorboard fastener heads by pushing a pin into the styrene planks – 3 near each end and 3 in the centre of each plank – that’s a lot of pinholes! 1x4mm strips of painter’s tape were used to represent the top faces of the door hinges that were set into the floor of the prototype.

There’s a few other embellishments to be added, such as bolt heads of canopy glue on strapping and other fittings. However, the focus now shifts to the chassis and underfloor detail.


























































