Modelling: 2mm scale wheels for diesels and electrics

An investigation in to the practicalities of 2mm scale wheel conversions and how it is done.

The 2mm Scale Association has developed products that makes life considerably easier for those wishing to convert off-the-shelf ‘N’ gauge D&E locomotives to run on 9.42mm gauge, 2mm scale track, unlike some finescale organisations working in other scales. The latest locomotive wheel sets from the society are put to the test in the new Graham Farish Class 31.

CONVERTING Graham Farish diesel and electric locomotives to run on 2mm scale track gauged at 9.42mm is, with the odd exception, easier than many modellers might expect. The release of a new Class 31 model from Graham Farish including the recent addition of models of the ‘refurbished' locomotives caused some problems with 2mm scale conversions because it has different sized wheel sets and final drive gears compared to the original model. The change in wheel design and the number of teeth on the final drive gear prompted the 2mm Scale Association to issue a new wheel set for the powered axles.

The new wheel sets became available through the 2mm Scale Association earlier in the year with an announcement in the April/May edition of ‘The 2mm Newsletter'. Its release provided the perfect opportunity to explore the drop-in wheel set system developed by the 2mm Scale Association. How easy are they to use? A ‘refurbished' Class 31 model finished in Network Rail yellow as No. 31602 was selected for the project and converted prior to repainting in civil engineers yellow and grey livery.

New Graham Farish Class 31

The refurbished or life-extended version of the new Graham Farish Class 31 was reviewed in the January 2021 edition of Rail Express Modeller. It was found to have an excellent new drive and featured four powered axles in the same manner as the prototype. The middle axle of each bogie is unpowered representing the load bearing axle of the prototype which was slightly smaller in diameter.

Three versions of the model were released, each with class- and time-specific details. One model was finished in early 1990s condition in Trainload Freight colours with a headlight mounted at mid-height to the left of the cab front together with revised radiator grilles. The model, which fills the need of post-Privatisation modellers, is represented by No. 31602 finished in

Network Rail yellow, a late adaptation of two Class 31/1 locomotives with through wiring for Electric Train

Supply or ETS. When the supplied ETS fittings are left off the model and the mounting holes filled, the combination of low headlight position and radiator grilles matches a number of different late-life Class 31/1s making the model useful for several different painting projects.

Out of the box, it represents

No. 31602 as hired to Network Rail prior to its naming in 2007 as Driver Dave Green. However, the fittings applied by Network Rail as part of the locomotive's testing role are not supplied. The mechanism is the same one used on all of the new Graham Farish Class 31 models released so far making the new drop-in wheels particularly useful.

Wheels for D&E modellers

2mm scale drop-in wheel sets are available for a variety of different Graham Farish D&E models. The use of standard wheel sets and final drive gears in much of the Graham Farish range has conveniently limited the permutations to a few types of wheel, although new models may complicate matters in the future as models become more bespoke.

For now, wheel No. 3-301 will cover the bulk of the DMU classes whilst

No. 3-308 at 7.5mm diameter and sixteen-teeth drive gear matches a wide number of locomotive classes.

A set of drop-in wheel sets by the

2mm Scale Association including integral gears on the four driving wheels. The quality of finish is excellent for the price of each axle.

Loco wheel sizes

Three different wheel diameters are available: 6mm, 7mm and 7.5mm with either 14, 15 or 16 tooth gears. Non geared wheels (plain axles) are also available for unpowered bogies of multiple units.

For the featured post-2019

Class 31 model, two different wheel diameters are required. Full size Class 31s are fitted with 3ft-7ins driving wheels and smaller 3ft-5½ins centre axle weight bearing wheels equating to 7.16mm and 6.58mm respectively. The closest match is 7.5mm for the driving wheels and 7mm for the centre axle wheels.

WORKBENCH TOOLS

■ Jeweller’s screwdrivers.

■ Fine nose tweezers.

■ Locomotive cradle.

■ Fibre scratch pencil.

■ Back to back gauge.

Graham Farish Class 31 bogies simply pull off for maintenance making conversion as simple as one could wish.

Prices for the wheels are very reasonable making 2mm scale conversions affordable at £4.50 per geared wheel set and £3.00 for one with a plain axle. Each driving wheel set consists of an insulated axle with metal gear, integral bosses behind the wheels to limit side play, and turned metal wheels.

Wheel set features

The wheel sets produced by the 2mm Scale Association for its members are

Unclip the bogie sideframes by gently inserting a flat blade screwdriver into the coupling end of the frame to release the clip.

particularly nicely tuned and found to be perfectly concentric when testrolled across plate glass. The wheel sets have 1.5mm diameter axles and are manufactured with bosses on the rear face of the wheels to limit side play, the inner frames of the models' bogies being designed for the narrower ‘N' gauge wheel sets. Furthermore, it was noted during testing of several of the new Graham Farish Class 31s, there is quite a bit of side play with the supplied wheels which is tightened up with the 2mm scale wheel sets, an important point when running has to be tighter to gain the benefits of switching to 2mm scale.

Conversion

Four of the No. 3-306 wheels sets at 7.5mm with 14 gear teeth are needed alongside two each of the No. 3-318

The 2mm Scale Association released 7.5mm diameter driving wheels to suit the new Graham Farish Class 31 model earlier in the year. This article looks at how to use the drop-in wheel sets using a ‘refurbished' Class 31 as a test bed.

One of the advantages of the finer standards of 2mm scale is better running through track work. Those who haven't used Peco ‘N' gauge Code 55 and Code 70 ‘Streamline' track might not know that the flangeways through turnouts and crossings are very wide and can lead to wheels dropping down the gaps in common crossings (vees). This is eliminated with correct track building in 2mm scale.

Ï ‘N’ gauge wheels are over-scale in width to enable them to operate on a variety of ‘N’ gauge track types and very successful the standard is too. Appearance is compromised as a result, including wide tyres and deep flanges, although ‘N’ gauge wheels are much improved. Ó

After checking the rotation of the new wheels and lubrication of the bogie gears, the bogies are clipped back in to the model. Ï Í The completed conversion, ready for repainting and weathering. The wheels are bright, requiring careful priming and painting to blend them in after the model has passed through the paint shop.

Ï The wheels are clipped into the bogie inner frame and require care to remove without damaging the wiper pick-ups or the bogie to chassis contacts.

Ï The first of two bogies is completed. As each of the geared wheel sets are fitted, they are gently rotated to ensure that the gears have meshed correctly. Furthermore, check for any detritus that may have (inadvertently) got into the gearing.

Ï A view of the converted bogie alongside the standard wheels. There is not quite the same level of detail on the face of the new wheels. It is all hidden behind the sideframes anyway! Ï

The difference in appearance is noteworthy, even with much of the wheels hidden behind the bogie side frames.

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