Engineering something for the winter

or

Building a battery powered loco without burning the house down!

 

I run a simple analogue railway (the Wild West Sussex Railroad, featured in July’s Continental modeller) which is fine and dandy in the dry weather.  Up to late summer of the first operating year, track power was all that was available to me until a little windfall enable me to buy a live steamer – a 3-cylinder Shay.

This, then opened up the possibility of running the railway in moderately poor weather.  (Let’s face it, if the rain is going to pour down your face and off the end of your nose, being outside is hardly going to be classed as ‘fun’.)

My railway runs with two trains at any one time.  I don’t do shunting, uncoupling, or anything tricky, I just sit and watch trains go by.  OK, so I have one train, which, being live steam, and not re-fillable while in steam, needs a bit of attention, and then 100% attention for the next 20 minutes while it runs!  But what about something else as an interlude?  Battery power seemed an answer.

I’d been looking at various small battery powered chassis on the market, and I had an idea forming in my mind.  Richard at Brandbirght demonstrated his R/C Baguley Drewery to me, and I was hooked.

I rather liked the look of the little Bachmann 0n3 gas mechanicals, but a 4-wheeler is quite small.  I’d seen pictures the LGB model of the D&RGW shunter, and again, I liked the idea of the outside frames and exposed motion.  But really I wanted something with a six-coupled chassis, something that I could probably use with the IP Engineering 0-6-0 chassis.

In my mind, I could see a little engineering train with one wagon and a bobber caboose.

I looked at diesel the body kits from GRS, but while I was looking, the prices went up.  Also, to make them look USA style, I’d have to add some bits, and what if my bits weren’t up to scratch?  I’d have spent quite a bit of money on a body that didn’t look good (no, we’re not looking in the mirror here!)

I was still meandering through websites when I saw Alan Doherty’s Worsley Works advertising the Hudswell Clark diesel tractor in 15mm scale, but no picture.  After some emails to Alan where he provided a link to the picture, and sundry answers to my various ‘off-the-wall’ questions, he suggested his etch of the IOM Schoema diesel ‘Viking’, offering that it had good proportions and ‘presence’.

I went away, did my sums, checked dimensions of the chassis and reckoned that I could probably do it.  I promptly posted a cheque to Alan and within a very few days, the etch duly arrived.  I also ordered the IP chassis with a speed controller and a couple of headlights, and these also arrived in double-quick time.

Alan had offered nickel silver as he had that in stock, but I had not soldered n/s before.  I also had to come up with a means of mounting the chassis to the body.  This isn’t as obvious as it sounds, because, if you look at the loco, you’ll see that the footplate is very high.

Mistake number one.  I came up with a very good way of joining chassis to body.  It ensures good physical fixing, it allows for dismantling, and it ensures that the body sits square and upright on the chassis.  What it doesn’t do, is allow you to remove the chassis in one piece in order to mount the batteries and the electrical bits and bobs.  The net result that all of the electrical bits are there, but the wiring is horrendously messy.  That’s why there are no photos of the finished underside and technical bits, the sight is too embarrassing.

The Worsley etch provides chassis side pieces, and so I superimposed the IP chassis members on these and drilled through the IP fixing holes.  Then, having cut a recess from the n/s chassis sides to allow space for the three the axles, I sandwiched the n/s sides between the IP chassis spacers, and the steel IP chassis sides.

The next move was to solder the n/s chassis sides to the footplate, after folding the footplate to shape.  (Like most etched kits, the Worsley Works etches don’t have instructions, but everything is obvious, if you sit and think it through.)  Worsley etches don’t have a lot of locating tabs, and the chassis to footplate is no exception.  I placed the assembled chassis on the underside of the footplate and held it in place with ‘bluetack’ while I spot soldered it – works a treat – checked the chassis for position, and centre, then blasted away with the soldering iron.

Once again, novice soldering techniques gave me a bit of a problem with the n/s and a 30 watt iron, but when I changed to 145 degree solder, everything went swimmingly.

With these kits, you need to work out which order to do things in, and it seemed to me that the cab end was the place to start, as the cab backplate was all one piece including the buffer beam.  The cab has all sorts of bits and pieces to add, the worst being the shades over the windows.  I decided therefore to fit the spectacle plates, then the shades, before assembling the cab.  For good measure I also applied the etch for buffer beam strengthening as well.

I took some time in putting the cab together.  It is worth taking the time to work out the details of whether the sides overlap the ends (or vice versa), because at 1:20 ish scale, everything needs to be crisp and sharp.  Cab corners that aren’t an accurate 90 degrees will shout at you.

Once again, the bluetack is handy.  Having got one side and the back squared up, I spot soldered them, then went on to the other side, and finally the front.  Only after the whole ting was spot soldered, and checked for square, with one side being de-soldered and re-fixed a couple of times, did I then begin to fully solder all of the angles.  The fully soldered joint is, in reality, the point of no return as it is very difficult to clean solder from an etch and keep it in pristine condition.

The bonnet didn’t quite fit ‘perfick’, and I’m not sure whether it was my folding up, or the etching. The bonnet is one piece and the folds at the top edges are, in fact, small rounds which need rolling around something small and round (unsurprisingly).  It was the front grille that didn’t quite fit, but I used some waste n/s as a backing piece and then filled the joint.  I needed to do a little filling between the grille and the front buffer beam as well because I didn’t quite get that as spot on as I would have liked.

Finding a supplier of handrail knobs and wire was a puzzle until I saw Alan Whitaker of PPS Steam Models advertising handrail sets for Mamods.  I emailed him and he was able to supply lengths of handrail wire and knobs.  These knobs are threaded, with retaining nuts, and a nice chunky size, just about right.  I soldered the retaining nuts for good measure, because I had enough difficulty getting my hand inside the bonnet to do them up in the first place and I didn’t want them falling off at a later date.  I also added some extra handrails to give the loco a more USA type feel.

I then turned to the IP Engineering chassis.  I tried to follow the instructions explicitly and, with a bit of care, managed to get the motor and gearbox together and, with a bit of encouragement from a 12 volt transformer, turning freely.

The wheels and axles aren’t that tricky, except that the instructions tell you not to glue the bearings in place at a particular point, but they never tell when you are meant to do it.  I tried, but by the time I got to them it was a bit late and after some running, I found that one of the bearings was turning.  I dealt with this problem when I re-wheeled it.

IP suggest a method of quartering the cranks which doesn’t seem too easy. What does work is fixing all of the cranks tight on one side; fixing one of the cranks tight on the other side, with the remaining two fixed semi-tight.  Run the motor for a few wheel rotations until it all settles down then fully tighten the last two cranks – it works for me.

Painting – mistake number – I’ve lost count.  I cleaned the excess flux off with white vinegar, then washed the whole body in mild detergent, with no bubbles.  When dry, I sprayed it with an etching primer. Fine and dandy.  The plan was to spray the yellow and brush the blue.  Spraying yellow, well doing anything yellow, is difficult because yellow doesn’t cover.  I got too impatient and had the paint running.  It doesn’t show in the photos, but the runs are there alright.

I also used an unusual make of paint for the blue which was too thick and dried too quickly for all of the brush marks to disappear.  Some of this was negated a bit when I used a Humbrol spray varnish which, although it described itself as an acrylic gloss, dried as a fine semi-matt finish.

When all was finished and working, including the speed controller, I installed some lexan for the windows and fixed the cab roof on with impact adhesive.

However, we’ve jumped a step and need to return to the sorry saga of the electrics.  I had installed the LED lights, and decided that I would do all the wiring on a small circuit using strip-board, which I could mount in the chassis.  Having wired it all up, I found that the IP speed controller wouldn’t control the speed of the motor at all, it ran at max revs the whole time.  I had mounted the potentiometer with an extended tube so that it formed an exhaust pipe on top of the bonnet.

I enquired of IP about the lack of speed control, and they advised me that I had probably wired the thing the wrong way round and that I needed to change polarity.  This I did and blew the transistor with a few little sparks. I sent them the circuit diagram and they advised that they were unable to help me as the circuit diagram had ‘short circuits’ indicated.  I beg to differ.  If you look at the standard way of wiring a DPDT switch for reverse current, at first glance it looks as if you have a short.  All that I’d done was translated this wiring method onto a strip board and yes, at first glance it would look like a short – but the motor had been running in both directions with front and rear LEDs working directionally.  It was only the speed control that wasn’t working.  The next call to IP resulted in them suggesting that I needed a new speed controller kit (they don’t sell the transistor separately) and two new LED kits (one would now only flicker, while the other would not come on).

I was two seconds away from placing an order when I stopped for thought.  I ordered a controller kit from Cambrian models for half the price and waited.  Their controller is bigger, and I had to mount it remotely from the potentiometer.  It’s now in the cab, and is visible at close quarters – shame.  I wouldn’t have needed to do this if I hadn’t made mistake number 1.

However, the controller still refused to change the speed of the motor, but after some diagnostic calls to Cambrian, and a few trials, I was sent a new resistor for the controller and, hey presto, the speed changes as you turn the exhaust pipe!

Then came the fire!  I plugged in the battery charger, and suddenly smoke belched from the loco bonnet.  Something had caused a short and now the battery pack was glowing red, the wiring insulation was burning and I couldn’t stop it.  I burnt my fingers trying to rip the wires out, and eventually calmed it all down by using a cutter on the wires.  About 50% of the wiring was burnt out, the battery pack was wrecked, but the other electronic parts, and the paintwork on the body all survived.  I have now included an in-line fuse between the battery and the on/off switch (which, being double throw, also switches the charging circuit on).

So we were off and running.  Then the loco stopped dead on the track, with the headlight still on.  As I approached it, I could hear the motor running.  It had ejected itself from the gearbox and was lying on the sleepers, still running!  The motor only fixes into the gearbox by epoxy.  In reverse, the worm pulls the motor into the gearbox.  In forward motion, the worm is pushing against the gear wheel, and the epoxy did not hold.  I manufactured a strap to grip the end of the motor and go around the gearbox.  It has stayed in since that.

After a while, the wheels went rusty. I contacted IP and they replied that they allowed their wheels to rust naturally just like the real thing.  Yes, OK, but the difficulty is that we’re talking 1:1 size crud on 1:20 size wheels.  I bought some Tenmille wheels and worked a very ‘un-engineering’ like solution to fix them on the axles.  It was also at this time that I fixed all of the bearings to the side frames.  The Tenmille wheels have nylon inserts, so the loco runs quieter now as well.  I also had to use an un-engineering method to make the centre pair of wheels flangeless.

Battery power is a 7.2 volt 2300 mAh nicad pack.  It probably is a bit too light for the load of the train, and I’m thinking of making a lighter wagon.

The Engineering wagon started life as a second hand Bachmann Ore Car, sold to me as a 20 ft gondola.  While it was probably better than a 2 plank high gondola, cutting up the ore car is not for the feint hearted.  Once the bogies are off, and a bit of a false floor, the hopper part is simply one moulding.  I only wanted 4 planks maximum so, in desperation sawed off the top plank, thus revealing the way to cut out the hopper from the sides.  It’s a bit crude and means that towards the ends, there’s no timber-like moulding marks on the inside, and the remains of bad saw cutting can occasionally be glimpsed.  However, other rough hacking of the sides, once treated with sandpaper, and painted, looks for all the world like timber that has seen some heavy use and abuse.

A new deck was made from lengths of stripwood, glued in place with two-part epoxy, thus rendering the body totally rigid again, and usefully gluing in the sub floor in place at the same time.  The sub-floor contains the bogie mounts, so you need that bit.

I had made sure that I had bought a second hand wagon with steel wheels, but then immediately stole the wheels for yet another project (and another story), but the workbench, being a white metal kit from P&J models provides more than enough weight – at one end only.  In the end, the wagon has plastic wheels on the bogie under the bench, and metal wheels on the bogie at the other end.  An then there’s the real reason for building an engineering train, the Bachmann tool kit set, which is liberally spread around the place with appropriate dollops of glue, as can be seen.  This I had been given one Christmas, and had been planning its use for a long time.

The bobber caboose didn’t escape lightly either.  With an Aristo 20 ft sprung chassis to hand (part of the other story), I decided to convert the bobber to a sprung mechanism, cutting away the Bachmann wheelsets, and inserting a lump of Aristo chassis into a suitable hole cut in the Bachmann floor pan. It certainly is a real ‘bobber’ now!

The crew are an LGB American train crew set of four people.  One driver is in the loco, another driver is sitting, looking very cold, on a crate in the wagon.  The third driver (identical to the first, but a different colour) had his wrist snapped and re-glued so that he could grasp the upright of the roof ladder, while the erstwhile fireman was dispossessed of his shovel and is now heroically trying to turn the brake wheel – for some reason.

The outcome.  7.2 volts is probably OK for the flat, but I have a couple of unintended gradients which seem to tax the power supply when it’s slightly off full charge.  The wagon is quite heavy and I have just acquired an even better 4 wheel wagon chassis (even better – ‘cos it was free!) and I’m thinking of making a lighter load for this one.

The loco probably still needs a bit of bedding in.  The IP gear mesh can be quite tight; one of the drawbacks being that you cannot see the mesh when you are assembling it, and as I said earlier, it took a bit of encouragement to get it turning.  Better by far, though, than being too slack.

The loco runs much more sweetly in reverse. So that’s how it runs most of the time.  The speed is fine, and I use the controller to stop and start smoothly.  Rough starts in the early days could be one reason why the motor selected self-eject mode at one point.

So now I have something to operate on those days when the Shay is steaming, and I am as mad as anyone else for being out in the garden playing with my trains.

 

Ian Watts - 2007.