Part two - making something special

John Cockcroft - Photos by the author

go to Part 1

The first instalment in the February Gazette described taking the model out of its mothballed state and continuing the construction of the tender and firebox. This second part concentrates on the chassis, running gear and body.

Locomotive chassis 2

The most peculiar parts of a B6 from a model builder’s point of view are the cylinder and slidebar assemblies. Dave has designed these as bolt on units with a back plate that sits against the frames. This is a good idea because Robinson was bothered about the length of the connecting rods and so moved the slidebars and crosshead well back from the cylinders and used a very long piston rod between them. Let’s be frank, this is a complicated unit but Dave has made it as simple and foolproof as possible.

The cylinders are pretty normal but the slidebars are odd-looking, with a front plate that includes a step. There s also a rocking valve rod at the back – though to make it work would be one of those masochistic “because it’s there” exercises – to which I am immune. There are also drain cock operating links to be fitted. So I proceeded with care and fitted each part at the easiest time. The slidebars and crosshead are lost wax castings and I got those assembled and fettled so that they fell in and out by gravity then fitted them and did the same with the cylinders and piston rod.

The basic rolling chassis with the flush fitted front crank pin. I painted and lined the driving wheels very early on in the build but forgot the balance weights

The front plate and step are a fold up etching and I got them in place ensuring they didn’t foul the free movement of the crosshead. Essentially it is an exercise in quick soldering, holding parts in the right place and burned As is the case with many outside cylinder locos I had to make the front wheel crank pin as close to flush as possible, to avoid it fouling the connecting rod. For a start I never fit the thicker bearing etch on the front coupling rod so the rod is thinner. Secondly I allow no side play on the front driving bearings, Thirdly I make the crank pin nut as flush as possible; the best way is to replace the 12BA crank pin with a 10BA screw and tap the top hat crank pin bearing 10BA so you can screw it on the pin and use the flange to retain the coupling rod. Alternatively, you can buy realistic lost wax crankpin nuts that are thin and can be tapped to fit the 12BA crank pin.

The left side cylinder unit after all the detail has been added.

I painted and lined the cylinder units separately as they are easy to get to in that way

With regard to tight radius curves, once I had got the chassis and loco body to negotiate my test curve, I decided that the loco and tender link should be dealt with and tested. For attaching the tender I generally use the crude toy train method of a flat plate projecting out from behind the loco and a solid pin on the front of the tender that fits in a slot in the plate. This has a number of advantages: it is crude and easy to sort out; to attach the tender you just drop the pin in the slot; you can use the plate to carry some of the weight of the tender which holds down the back of the loco – ideal for 4-4-0s and some 4-6-0s. So I put the loco and tender on my test curve and measured the distance between them at the centre line and arranged the slot in the plate at a suitable spacing.

After I had built the basic body I went on to detail the chassis. Here you can see that I only fitted the top part of the inside valve gear – the lower parts to my mind are just invisible clutter.

Apart from the cylinder unit the rest of the chassis detail is not unusual, and the instructions, etched parts and castings for replica inside-motion, brake gear and other details are pretty clear, so there is no need to repeat that here. In the case of the inside motion, I only modelled the top half that can be seen under the boiler and cut the valve and connecting rods well short of the middle axle because that was where the motor and gearbox were located. I also missed out the bottom slide bars and crossheads as they are close to the bogie. I will only add that I spend a lot of time checking and testing as I fit new parts to ensure surprise short-circuits and binding wheels etc are dealt with when they first rear their ugly heads.

The Great Central bogie is quite complex with outside equalising beams and springs. Here you can see the additional pick up arrangement I installed. The 0.5mm wire wipers are lightly in contact with the wheels and are intended as a supplement to the main pick ups. The connecting wires to the chassis are not installed in this photo – they came almost last. You can also see the wire restraining arms that project inside the frames and control the side play of the rear part of the bogie as there is little room in there.

With many outside cylinder locos the problem of getting the connecting rod past the leading crank pin is highlighted in this photo – along with the solution. The crank pin at the top is a brass bush tapped 10BA and the crank pin is replaced with a 10BA screw. The bush is screwed onto the pin with the flange on the outside. Note also that the leading coupling rod bearing has the outer layer omitted to keep it thinner.

Completing the body

This is the home run. With all the main parts assembled there remain the bits and pieces to make the model look like the real thing. The B3s were in practice not the most efficient and successful engines – very much like a lot of other big 4-6-0s of the early 20th century. So almost from the start there appeared modifications and alterations that are there to trip you up if that sort of thing bothers you. Quite a few of these changes are accommodated in the kit but the best option is to consult the books mentioned at the start of this article. I tried to make my model represent Earl Beatty’s condition in the early 1920s, when it was used on the East Coast Main Line for a period. But first I had to put the cab roof on – which didn’t change much over time.

The roof is quite unusual and appears to be built tight to the loading gauge at the eves, so the first job is to roll it to almost exactly the right radius using the cab front as a template. There are riveted ribs across the front, middle and end of the roof and a rib on the underside where the cab sides end. These also help to get the shape right. However I started by carefully tack-soldering the roof to the cab front where there is no location except the line below the riveted rib at the front. I then tacked it to the top of the cab sides. I found that the part that sits immediately above the sides is best bent down a shade, but it must hardly overhang the sides at all. When that was done and looked OK I began soldering on the ribs and the rain strips, which because I was so careful about getting the curve of the roof right, fitted really well. In the end I was pleased with the result and I think it catches the distinctive look of the roof very well.

The cab roof is quite complex but everything fits if you make sure the curvature of the roof is accurate. Note that the eves of the roof have very little overhang at the sides.

Before I went on to detail, I linked the loco to the tender. I did this in my usual very toy-like way by soldering a 2mm diameter rod down from the front of the drag beam on the tender. Then by measuring the distance required between loco and tender on my tightest curve I established the location of the slot for the draw pin. The pin locates through a flat plate projecting from under the loco drag beam. The plate is an L-shape with the vertical part soldered behind the drag beam and horizontal part then drilled and made into a slot for the draw pin. This system is simple and very effective, and if required the plate can take the weight of the tender front – holding down the back of the loco.

Here the model and tender are on my five foot radius test track. The photo gives no indication of the messing about involved in getting such locos round too tight curves.

I will not dwell too much on detail but make a few observations. I went ‘all detailed’ sixteen years ago, so I drilled little holes in the footplate above the cylinders to take a series of small oil feeds. I used some 4mm scale WD Austerity handrail knobs I had from decades ago and wired a fictional cat’s cradle of fine wires to them – don’t copy them as they are pure guesswork! The B3s had a rather elegant chimney when built but in the mid-1920s they were replaced by a coarse and ugly flowerpot type. However, from the early 1930s they replaced them again with a much more attractive design which resembled the original. I used the original design but you could send off for the flowerpot type when the kit was in production. I also used the original type of superheater header discharge valve on the left side of the smokebox, which requires the handrail to be interrupted. The LNER soon replaced those with mushroom style snifting valves behind the chimney.

Detail on the left side of the smokebox and footplate. The GCR superheater header discharge valve and associated pipework are applicable only to the GCR and early LNER period. Don’t look too hard at the pipework on the footplate as it is largely based on imagination!

Detail on the right side of the smokebox. Again the cat’s cradle of pipes on the footplate. The pipe on the side of the smokebox was much shorter in the GCR period but was soon extended by the LNER.

The right side also features a prominent reversing reach rod which in my model I fitted after painting the engine. I used 14BA screws at both the support on the splasher top and the reversing arm so that the rod could be removed. The washout plugs on the model are the earlier version which were replaced later in LNER days.

I could go on, but it is up to you to do the research. Many of the class including Earl Beatty were fitted with ugly, boxlike rotary valve cylinders during the 1930s. Some survived in original form until after the war when they were in a filthy neglected condition – but that is a matter of taste. I finished mine in early LNER green with the number on the tender. Photos of the B3s early in the LNER period show them in lovely clean condition and that is how I finished mine – and that is how I like it. But if you want to spend a ha’porth on tar and avoid lining, model the 1940s.

This is a great kit and produces a model that captures the elegance of these attractive engines. If enough of you take the trouble to enquire with David Andrews about a short production run of these kits you may be able to acquire one.