Dual motors and wheels for Hornby EMDs
A return is made to the workbench for a session of tinkering with wheel and drives to see if there is mileage in working with the Hornby Class 59 and Class 66 models. The results were surprising to say the least!
THE SWATHE of Class 66 models together with the occasional Railroad-branded Class 59 released by Hornby over the last few years, have proved to be very popular, prompting some thought as to why, when there are high-fidelity ‘OO’ gauge Class 66 models available from other manufacturers and a brand-new
Class 59 is on the horizon. Budgets may have something to do with it, alongside loyalty to the Hornby brand.
Last month’s project to model GB Railfreight No. 66708
- Glory to Ukraine showed that the Hornby Class 66 can be detailed and painted to produce a convincing model, and within a tight budget too.
Recently, Hornby released another Class 59, this time a Class 59/1 in Hanson livery. It is one of the popular former Lima models which has potential for enhancement. In fact, working with the range steps back into a world of locomotive detailing which was once an important part of the hobby.
Former Lima models
It appears that the former Lima range now produced by Hornby with upgraded drives and details has relevance today from a financial viewpoint. As household budgets become ever more squeezed, modelling funds are likely to be reduced and £175 to £225 locomotive models might not be affordable for some modellers. Hornby produces its share of highly detailed models at the £200-plus price point, but for many, the Railroad range can provide a means to equipping a layout with convincing models and for around half the cost.
Many of the former Lima models offered by Hornby are still highly regarded. When produced by Lima, they were let down by poor drives which were hit and miss at times. Modellers upgraded them with additional pick-ups and dual motored those required to haul long trains. Inadequate details were replaced with brass ones and lighting began to appear as DCC became more widespread.
Hornby’s Railroad range diesel locomotives are basic compared to its main range. The motor is bogiemounted instead of being fitted to the frames in all but the Class 20 model, in the same way as when they were produced by Lima. Furthermore, the three-axle bogies are a one-size fits all which means that the centre axle is slightly out for EMD locomotives in both the powered and trailing bogies. The lack of powered axles (only two per model) sees the use of traction tyres.
Testing has already shown that the upgraded drives with their axlemounted drive gears perform far better than the old Lima ‘pancake drives’ including the EMD locomotive models prompting a look at the latest Class 59s and the model of No. 66708. Can they be upgraded for operation on an ‘EM’ gauge layout and with enhanced performance without breaking the bank?
The powered bogie as fitted to Hornby’s EMD models. The bogie side frame moulding is clipped in at the ends (A) and along the sides (B) making it tricky to remove. The model relies on traction tyres for haulage power from the two driven axles (C).
A completed set of wheels which have been mounted on their original axles. There is sufficient length plus the size of the wheel bosses makes this possible to do without having to buy new axles.
Workbench tinkering: starting with the wheels
The first project undertaken at the workbench was an experiment to equip No. 66708 with ‘EM’ gauge wheels without buying an expensive conversion pack. It required a deal of tinkering to work round the 2.5mm diameter axles.
The economical way forward is to attempt to use the wheels supplied with the model. A close examination showed that the flanges are deep and with a tyre width of around 2.8mm, they cannot be pulled out to ‘EM’ gauge (16.5mm back-to-back measurement) because the widened wheel sets will not fit the bogie frames.
The two drive wheels fitted with traction tyres were replaced with spares before they were reduced in width using a crude but effective method. If you have access to a lathe, then the use of a lathe is preferable. However, a good quality and powerful mini-drill will also do the job provided it is fitted with a good chuck that rotates without any wobble. It is not accurate enough for reprofiling wheels as can be done with a lathe. In this case, all we need to achieve is a small reduction in flange depth of about 0.5mm and a reduction in the width of the wheel.
Black Beetle wheels fitted to the stepped axles were installed in two motor bogies destined for a single Class 59 model. Note that the middle axle remains to be adjusted to align with the axle box detail on the bogie sideframes. Note how much axle stands proud of the wheel.
Hornby’s replacement for the old ‘pancake drive’ bogie has gears fitted to the axles of the powered wheels. The axles are 2.5mm in diameter making the use of commercial wheels difficult.
The wheels are test-fitted to the model. The drive gear boss prevents all but a little side play of the axles. However, a shim washer on either side of the gear further reduced side play for good tracking through ‘EM’ gauge track.
Reducing the wheel size
This method requires the drill to be mounted securely on the workbench to hold it steady. An axle is fitted to the chuck and each insulated wheel treated in turn. The flange is reduced first using a high quality fine-cut file applied carefully to it, followed up with grade 600 wet and dry paper. Use a vernier caliper to measure the flange depth as work progresses.
About 0.2mm is removed from the rear face of the wheel to slightly reduce the flange width, using the same file, taking care not to reduce the width too much. The remainder is removed from the front face until the wheel is 2.4mm wide which will fit in the bogie frames of both EMD models when assembled to ‘EM’ gauge. Clean up each wheel with fine abrasive paper to polish the tyre and rear face so the model’s pick-ups will work smoothly against them. The bonded wheels are turned whilst still attached to the axles.
Shim washers are usually fitted on either side of the drive gears to reduce side play in the axles after conversion to ‘EM’ gauge. An alternative method is to fit pads of 0.125 metal to the inside of the bogie frames when using the stepped axles, which are quite long. The axle ends make contact with the pads, reducing wear of the side frames. Axle side play is reduced to a minimum as a result.
Thinning the Hornby wheels to allow them to be regauged to
‘EM’ gauge was found, after some experimentation, to be possible. They had to be reduced from 2.8mm in width to a maximum of 2.4mm. The flange was reduced in depth by 0.5mm.
Adjustment of the middle axle to align it with the axle box detail is shown in this image. Note the phosphor-bronze strips used to spring the outer axles for better tracking.
Wheels assembled using stepped axles including three axles fitted with Bachmann 14mm coach wheels which have been reduced in width to 2.2mm. The best method is to remove the plastic boss from the wheel and attach it to the axle before pushing the wheel into place.
Wheel assembly
It is possible to use the model’s original axles for ‘EM’ gauge. They have sufficient length, which when combined with a generous boss at the rear of the wheels, form a secure grip when set to ‘EM’ gauge. Knurl the axle ends by rotating them between two files to enhance the grip, together with the use of Loctite securing compound once the gauge has been set to 16.5mm back-toback measurement using a gauge.
During assembly of wheels, check that they run true by rolling them up and down the workbench to see if there are any wobbles and, when found, use the back-to-back gauge to straighten them.
The driven axles have their drive gears refitted as part of the conversion, locked with a touch of Loctite if necessary. If the cost of Loctite blows the budget, a high viscosity superglue can be used instead. The gears have a boss on either side which reduces wheel side play. When converted to
‘EM’ gauge, shim washers are needed and are added to each axle during reassembly.
Another option is to use EM Gauge Society stepped axles to fit wheels with 2mm axle bore to Railroad range models. It is a very simple way to undertake
‘EM’ gauge conversions for former Lima models and almost any wheel can be used as long as the plastic boss is trimmed flush with the back of the wheel.
A completed wheel is shown being buffed with increasingly finer grades of abrasive paper to remove any marks from the thinning exercise. The wheels are not actually reprofiled: a lathe is needed for such tasks.
EM Gauge Society axles
The EM Gauge Society store offers a stepped locomotive axle of 2.5mm diameter suitable for Hornby railroad diesel locomotives (available to society members only). They are 23mm in length, with the ends turned to 2mm in diameter to accept suitably adapted commercial wheels. One successful experiment involved Bachmann 14mm diameter coach disc wheels which were reduced in width to 2.2mm and mounting them to stepped axles.
The same concept worked with Black Beetle and DCC Concepts 14mm disc wheels made to RP25-88.
It was possible to remove the bonded wheels from the latter’s wheel sets and fit them to the stepped axles. Some wheels need the axle ends knurled for a good interference fit and once again, Loctite can be used to complete the bond. There is no knurling in the middle of the axle to hold drive gears. This has to be introduced using files as before. As each wheel set is assembled, they are checked in a backto-back gauge and examined carefully for eccentricity.
Setting up and testing
When assembling the wheel sets using stepped axles, some thought has to
be given to axle side play within both the powered and unpowered bogies. Shim washers can be fitted between the gear and the bogie frame. It was found that the 23mm long axles came into contact with the inside face of the bogie frames due to side play. An alternative to shimming the axles is to fit small squares of 0.125mm metal sheet from etched fret to the inside faces of the bogie frames adjacent to the axle box detail to reduce side play and wear. The ends of the axles should be smoothed and a small amount of lubricant may also be necessary.
The results
Tinkering at the workbench is always a learning exercise which one hopes will deliver results that ultimately improves performance of locomotives, stock and the layout too. Both methods for adapting the Hornby EMD diesel locomotives were very successful, particularly the stepped axles which were eventually used in a dual motored Class 59 (see below). The big surprise was the ability of the single drive Class 66 (GB Railfreight No. 66708) to haul 13 Accurascale JTA/JUA bogie box wagons on level track without difficulty. Lacking traction tyres, inclines would be out of the question, but the tractive effort was more than was reasonably expected from this model. Additional weight improved matters further, together with a Lenz ‘Silver’ decoder which suits the Hornby drive quite well.
Tracking with the reworked wheels was good through all manner of track work, proving that a simple reduction in wheel width and flange depth is a viable way of obtaining an ‘EM’ gauge model for minimal cost.
Closing notes
The subject of affordable modelling will be the theme of articles in the future, where the modelling potential of the Hornby Railroad range and others will be further explored. Whilst a Class 59 can be bought for a discounted price of around £81 at the time of writing, some care has to be taken over how much work is applied to the model if costs are to be controlled. Adding the cost of an additional motor bogie, a lighting kit and detailing parts could bring the cost of the project to within 80% of that of a super detailed model, so some care has to be taken when buying in parts! Nonetheless, if only one drive bogie is required, a fully fledged and detailed Class 59 or Class 66 can be modelled within £100 and careful tinkering with the wheel sets at the workbench could see an ‘EM’ gauge conversion achieved within that cost zone.
Rail Express Modeller would like to thank the EM Gauge Society Trade Officer for his kind assistance with the stepped axles. For more details, visit