The fixing screws

The chassis is held to the main body with screws at each end.

I've already fitted the nuts on the outside frame assembly, now I assume I have to drill holes through the chassis to fix the pieces together.

I hadn't been thinking about that when I filled the areas in question with lead shot recently, so I have to remove most of it to drill the holes.

With the frame fitted onto the chassis I start by drilling through the nut from above, gradually increase the drill size, hoping this way to get the holes in exactly the right place. They have to be increased to about 1.3mm to comfortably fit the 12BA screws.



The first one ended up nearer one side, so I had to "move" the hole to the right by reaming with pressure on that side. Although the chassis now runs, it looks from the photo as though I'm not quite central yet.

I do better on the second hole.

body held with 2 screws

Now I find I've introduced a short-circuit. Turns out, when the screws are tightened, they push the PCB underneath the body assembly against the tabs on the top of the chassis.


I probably don't need the screws absolutely tight, but as a precaution I put some sticky tape over the tabs.

Finally I need to cut back one of the screws to keep it clear of the motor. I use a tip that I picked up from my 2mm colleagues recently.

I wound 2 nuts onto the screw before cutting it with pliers.


Once the rough end is filed off, the nuts preserve the thread as they are removed.

short screw clears motor terminals

Fitting the cranks

I've done a little background reading on fitting cranks and quartering them, such as descriptions of how people align the cranks by eye then "fine tune" them by rotating one wheel fractionally relative to the others.

I'm not sure how relevant this is. Since I've already got the balance weights aligned and quartered (by eye) I want to try to glue the cranks onto the wheels using the connecting rod as a jig. However there is some play between the gears, ie each axle can rotate a few degrees relative to the others, so there is no absolute "correct" alignment, and I expect that for this reason I may end up enlarging the holes in the rods to allow for the play. Time will tell.

Still I must mention one tip that I came across - someone uses a set of "loose muffs" so they can slide the wheels on and off easily for testing during construction. Wish I'd thought of that a few months ago...

"Work slowly and carefully", the instructions advise. I'll check things at each stage by making sure the chassis still runs downhill when I tilt my test-track in both directions.

First I check the fit of the crankpins in the rods, and have to open some of the holes out slightly so that the pins will fit through perpendicular to the rod.

Now I fit the first crank on, opposite the balance weight, making sure the pin is perpendicular. Waiting for the epoxy to set I remember I should have cut back the pins before fitting them.


Managed to cut the pin with wire-cutters. I allowed enough for the coupling rod, the fixing washer and a little extra to work with.

Next the front crank. As the glue sets I make sure I can turn the wheels gently. So far so good.


I've filed the first 2 extended axles back to allow the coupling rod to turn freely.

Then the third crank. The clearances are tight, but once I've removed every scrap of excess glue from the axles it still coasts downhill.


For the other side, I cut back the extended axles and crankpins as much as possible before starting.

Then I fit the cranks as before, with the rod still in place on the other side.

Well I'm happy to say, it didn't go that badly. I still have to fit washers to the crankpins (see the left axle above), but till then I'll keep the rods in place with plastic wiring.

The marker lights

These are fitted front and back above the bufferbeams, attached together by cable.

They're a two-part etch. There's enough material for twenty lights but I only need four, so I can experiment a bit.


Once cut down the middle the part-etches can be overlaid. The part with a slit goes underneath to make a hole for the connecting cable.


I make a couple and cut them off but find that even the tiny sliver of solder I've used is enough to fill in the holes.


They're about 1mm long and it's beyond me to remove the solder. Perhaps I should build them with the wire in place.


The thinnest wire to hand is overscale (0.25mm). I glue the other half-etch on top of it.


The wire is very obviously too thick.

I wasn't able to locate any 0.15mm piano wire, but I got some gauge 8 guitar wire (0.2mm).

Eventually I find a method that works for me. Some part-etches seem to be larger than others, so I start with the large ones.


Use the jigs to cut the wire to length. Solder it onto the lower half-etches. Allow enough solder to bring it level with the wire and file flat.


Fix the top halves with epoxy and trim to shape.

The lowest set here uses the smaller part-etches. I'm not sure which are nearer to scale but I think the larger ones look better, possibly because they make the overscale wire less obvious.

Finally, and this may be too ambitious for me, once fitted the front cable should extend round one side of the bonnet, down and across the steps. I've got several metres of soft brass wire to practice with.

Building the cab

The cab structure is a combination of metal etch with resin roof.


wooden cab door (left) and steel door


cab window etch

Some locos had a frame around the cab window, but mine is plain glass.

The doors are soldered onto the etch for strength before removing it from the fret.

cab etch with doors

Bending the sides accurately is tricky, particularly avoiding the delicate windscreen wipers. Without a folding tool I’m using 2 pieces of brass bar to support the etch next to the folds. Eventually it goes wrong. One of the doors comes loose and the frame bends.


I’ve removed the door on the right.

With the etch flat on a piece of glass I push a brass bar across the bent side with increasing pressure. When flat I replace the door with epoxy glue.


Doesn't look too bad now. The roof isn't glued at this stage.



I’ve made some windows from 0.25mm clear styrene. I’d like to model one of the cab windows half-down but I’ll need some thinner material for that. In any case I won’t fit the windows until the cab’s painted.


** May 2007 **

Yes my friends, I folded the cab inside-out.

After unfolding it, reversing the doors and folding it back there were three casualties.


(1) The thin section at the top of the window developed a kink that I haven't been able to remove. I'll have to fill it and file it flat.

(2) One of the windscreen wipers came off, and since they were both too bent by now I decided to replace them with some thin wire.


They're under 3mm long, made from 0.1mm electrical wire. I've glued the arm on top of the wiper so that when fixed the arm will be clear of the glass. I'm working at the boundaries of my dexterity and patience here - really wish my hands were a bit steadier.



(3) One of the upright tabs came off, but I managed to solder it back.

For a few days I was too annoyed with myself to work on this. Feeling better now though, and ready to move on...

The bonnet sides

left bonnet doors

I’m tempted by the look of the riveted bonnet doors (left), but for my choice of prototype I need the pressed steel doors with cut-out for the air compressor unit (below right).


right bonnet doors

Four options here. I need the pressed steel doors with cut-out for the vacuum exhauster (below right).

There are lots of handles on the bonnet sides.

bonnet handles etch


There’s a template for drilling the holes to locate the handles accurately.


I had to file the lower left-hand edge to allow it to lie with the four square holes matching the grille marks on the body. Securing it with crocodile clips I can drill 0.3mm holes through the body.

My new “archimedean” drill broke the first bit straight away. Obviously a skill I need to learn. Had more success with the bit held in a pin vice, twisting quickly and pressing gently, but one lapse of concentration and another bit snapped. Glad the good people at “Eileen’s Emporium” had advised me to buy their less-expensive bits.

holes drilled



There are 2 options for the bonnet side grille. I need the one with the thin wires inside.


And a cover at the base.



There's a cover on top of the left-hand fuel tank. I'll need the flat one.



The fuel tank cover and bonnet sides are fixed with epoxy. The side grille will need to be removed for painting. I've added one handle for effect - I’ll fit the others later to avoid damage.

Adding extra weight

I've recently been looking at some of my old N-gauge locos. Armed with the confidence and knowledge I've gained through working on this kit I took apart my
temperamental Farish railcar . Happily I did manage to get it back on its wheels, and it was also interesting to look at a different method of chassis design at first hand.

Anyway, it convinced me that I need to get as much extra weight onto this loco as possible.



I recently bought this lead shot. I thought it might fill various gaps more effectively than a single thickness of lead sheet, and also I didn't fancy cutting it to size.

First I’d like to have some extra weight below the footplate, giving it a lower centre of gravity and hopefully more stability.


There are sections at each end of the chassis that could easily be used.


A simple styrene sheet base with dividing strip to maintain the "split frame"


I glue the shot one layer at a time.


I'd been advised to use PVA glue, but it didn't hold strongly enough so I'm using epoxy.



The boxes on the footplate are straightforward.



The motor itself is fairly heavy, but if I need it I'll also have room for extra weight around the terminals under the bonnet, and hopefully also in the cab to balance it out.

Fitting the wheels

I've been thinking about how to fit the wheels for some time ("putting it off" might be more accurate). Seems that people have their own methods, and the instructions touch on this only briefly. I've looked at the design for a jig that fits wheels (and does the quartering) by tightening it a vice. But an Association member who builds his own locos successfully with relatively simple tools has described his method for fitting and quartering wheels which I plan to follow.

First file a chamfer on the end of each wheel axle


I'd already opened up the muffs with a 1.5mm drill. Now I need to drill a 1mm hole through the centre of the muff. This is to allow release of air as the tight-fitting axles are pushed in.


A final check that the chassis sides are still electrically separate, then I fit the first axle by turning each wheel by hand with gentle pressure inwards.


I've put a small washer on this axle to reduce sideways play.

I'd previously calculated that I needed a 0.45mm gap on each side between the wheels and chassis and now I need some spacers.

simple styrene sheet spacer

The key dimension is the distance between the back of the wheel rim and the chassis side. So the gap in the spacers has to be big enough to go around the small raised section visible around the axle, allowing the spacer to lie flat against the wheel. I cut some from 0.5mm thick styrene sheet.

Now with the spacers in place I can gently twist both wheels inwards until they are tight against the spacers. The first axle turns freely so I do the same with the central axle.

spacers on central axle

Now the gears are locking. Even though they had previously been running smoothly, I have to spend quite a while running the wheels along the test track by hand to loosen them up again.

Next to add the final axle, tighten the wheels to 8.5mm back-to-back (or just over) and turn the wheels so that the balance weights are aligned on both sides, with a quarter-turn difference between sides.