Highland Railway Loch class 4-4-0

Review by Sandy Harper

Loch Ness, but no Monster!

Engine No 120, Loch Ness, was one of the last designs of passenger locomotive for the Highland Railways by its Locomotive Superintendent, David Jones before his death. They were popular with the footplate crews and engineers alike for their excellent handling and ease of servicing. When they were introduced in 1896, although modern in their engineering, they still retained some of the old Highland Railway peculiarities like smoke box wings, louvred chimney and domed top cab roof. The Lochs were to be found all over the Highland system because their 4-4-0 wheelbase allowed them to negotiate the sharply curved track of the far north and Kyle lines as well as being strong hill climbers on

Having previously build a model of a Peter Drummond inside cylinder 4-4-0 version of the Loch, the ‘Small Ben', I quite fancied a go at the outside cylinder Loch which is available as a kit from Andy Copp at Lochgorm Kits.

I hesitate to class this as a kit review for two reasons. Firstly, what Andy supplies is described in his catalogue as an ‘aid to scratch building' and consists of a set of brass etchings blown up from a 4mm design originally drawn by Alisdair Wright of 5522 Models. Andy also leaves the builder to source their own castings, wheels and motor/gearbox. And secondly I messed about with both the tender and loco chassis for my own particular requirements.

So what follows is a series of notes on how I achieved what is effectively my version of building a HR Loch class. Considering its 4mm origins I found very little difficulty in assembling the etches and it went together much better than some other offerings on the kit market that I have experienced.

All the castings for both the locomotive and tender can be supplied by Laurie Griffin and if you ask him for the full scratchbuilder pack he will probably offer a generous discount on the catalogue price of the individual items. Wheels, buffers, handrail knobs and motor/gearbox will also need to be sourced separately. I obtained the loco wheels and buffers from the Slater’s range and the tender wheels from JPL because I needed two axles with uninsulated wheels for split axle pick-up, and the third (rear) axle insulated both sides. The motor is a Mashima 1833 fitted to a Premier Models gearbox that I had in stock; it fits well.

Tender

I started this build, as I usually do, with the tender. I wanted to use my now standard split axle pick-up system, but found that it was not possible to modify the supplied internal chassis to use the Slater’s insulated horn blocks, and that I would need to scratchbuild a new set of frames.

Original frames that would not accommodate the insulated horn blocks.

This was straight forward using 0.028in nickel-silver sheet that I had in stock. Assembly was with the usual L shaped spacers. I make the rear axle bearings fixed, and spring the front two, using the insulated horn blocks. The front two axles were split using the drill, saw and glue method. New tender frames under construction to accept Slater’s insulated horn blocks..

New tender frames.

Pick-up was arranged through sprung steel wires bearing on the square brass bearings and attached to a small length of copper-clad fibre glass board glued to the inside of the frames to maintain the insulation of the power through the wheels, via the bearings, to the motor.

On tender engines I only pick-up via the tender and the locomotive remains electrically isolated. Electrical power is transferred to the motor in the locomotive by a miniature plug and socket between the loco and tender. This has a number of advantages. No pick-ups in the loco, no shorting between the loco and tender, all the electrics can be housed within the tender including a DCC chip and speaker if required, and it’s all much more accessible than if installed in the locomotive. I can't claim any originality for this idea as it was shown to me by the Guild’s DCC Technical boys.

Split axle fitted to new tender frames.

Once the new set of frames was completed the rest of the tender etchings went together rather well although the comprehensive instructions about laminating the internal frame sides of the tender tank to the external sides was, I considered, superfluous (possibly a left over instruction from the 4mm version where the metal would have been much thinner). The thickness of the brass supplied gave the tender sides sufficient strength in their own right and so I only tacked them together rather than use the sweating procedure suggested.

Tender body showing internal framing.
Tender body complete.

What I did find though was that it would have been easier to bend the tank top to fit the shape of the internal sides, where it locates, before the external tank sides were attached. I built the long tender option so did not build the external rear tool box.

Locomotive

Because of the blowing up from 4mm to 7mm, some of the etched holes were oversize. This was mainly on the boiler, handrail knob holes, and on the footplate. Fortunately the handrail knobs I had in stock just fitted without falling right through.

The chassis is designed to use a clever compensation beam between the front drivers and the bogie and it was my original intention to adopt this method of construction. Once I had reduced the oversized pivot holes for the beam I tried to make it work but the motion bracket prevented full rotation of the beam and the only way I could see it working was with major surgery to both the beam and the motion bracket.

Loco chassis with front driving wheel bearing in slot.

I gave up and resorted to cutting horn block slots for the front driving axle in the 0.028in frames and fitted a pair of Slater’s square, slotted bearings instead, with a steel sprung wire resting on the bearings and attached to the inside of the chassis side frames. An additional goal post shaped piece of 0.015in nickelsilver was soldered to the inside face of the chassis side, around the bearing, to prevent it rotating. The rear driven axle was of course fixed.

To maintain the three points of compensation (three legged stool principle) the bogie is fitted to a centre pin with a height limit stop (the third point). A small amount of side-play is allowed for by making the pivot hole elongated. I also fitted a restraining bar to the rear bogie stretcher so as to limit the swing of the rear wheels. I used this trick in a Jones 4-4-0T to great effect to prevent the rear bogie wheels coming into contact with the rear inside faces of the cylinders.

Slots were cut in the bogie side frames for the fitting of Slater’s square bearings, (as per the front driving axle) and they were independently sprung with steel wire.

Bogie slotted to take square bearings.

I found it best not to solder the motion bracket to the frames until you have constructed the cylinders and slide bars as it is important to get these horizontal.

Note the final location of top of motion bracket. This little problem was caused by the cross head, which was the wrong shape. It was filed to the correct profile.

Clearance between the crank pins and the inside edge of the footplate, especially on the crank pin with the connecting rod, is very limited. Don't waste any space in this area and keep everything tight.

This little problem was caused by the cross head casting and the slide bars both having too much metal.
The problem was resolved by reducing in size both the cylinder/piston rod flange and the piston rod/cross head collar.

The fold-up etch for the cab internal splashers and floor was another area that I had difficulty with in that it did not appear to fit correctly. It was a simple enough matter to break up the components from the intended single fold-up piece, adjust to suit, and re-solder. </WRAP half column> Problem with footplate.
Resolution.

The rest of the body etches went together without much difficulty and I particularly liked the designers method of putting tabs on each end of the boiler barrel which then located into slots in the cab front and smoke box rear. This made the fitting and alignment of the boiler very easy.

Once all the castings were attached my usual cleaning process was commenced but this time with the addition of an ultrasonic cleaner. I was quite amazed by the amount of dirt that was removed by the machine even after I had cleaned the model, I thought, thoroughly using my usual methods. I also intended to have it grit blasted before painting but my grit blaster, having recently undergone a hospital operation, was out of action for a few weeks so it went straight into the paint shop and had a light coat of Halfords Acid 8 etch applied followed by two coats of Precision HR Dark Green.

The black areas on the locomotive were hand painted using Humbrol Satin Black No85 but the tender was sprayed all over first with a Black etch primer, which has a similar finish to the Humbrol, and was then masked off to apply the green. Ready for the paint shop.

I wanted to portray the loco later in its Highland career and so applied red buffer beams but still in the Drummond II plain livery. Transfers for the name came from Guilplates as did the cab number plates and builders plates. The remaining lettering is from the Fox range.

My usual varnish mixture of Ronseal Satin (polyurethane) mixed 50/50 with white spirit and a dollop of Humbrol Satin Black mixed in, was applied in a couple of thin coats to complete the model.

This was a pleasant and interesting model to built with one or two issues to resolve along the way, as detailed in the text. It is certainly not a beginners kit but well within the abilities of a competent kit builder.

Andy Copp of Lochgorm Kits has seen this article and writes: Thanks for the opportunity to respond to Sandy's review of the Loch kit. It is very fair and informative, especially in highlighting possible construction difficulties and suitable work rounds to accommodate the builder's preferred construction techniques. The tender brake rods will fit the original tender chassis frames. However, the review does highlight the problems associated with blowing up the artwork designed for 4mm to 7mm scale. Although Sandy found a few issues to resolve, he is obviously pleased with the end results. Making what is marketed as a Scratch Builders Aid into something just what you want is of course a good part of what model making is about.

Andy Copp