I am always on the look-out for a bargain, so when a Houston Gate Loco Works (HGLW) loco came up for sale on eBay for the princely sum of £25GBP, I snapped it up.
One of the things I like about HGLW locos is they come with a form of 4-wheel drive as standard, provided by a simple pulley system (See How I constructed a diesel loco from a HGLW kit). They also have a good quality brass worm-wheel, which tends to give them fairly reliable and smooth running characteristics.
As you can see, this loco was provided with a decent amount of ballast in the form of car balance weights.
The Electrics
The loco was powered by two non-rechargeable AA cells and controlled with a DPDT centre-off toggle switch wired-up as a reversing switch.
The reversing switch was mounted in the cab.
This arrangement allowed the loco to travel back and forth at a fairly realistic speed but, of course, to tie the loco in with the rest of my fleet, I wanted it to be radio-controlled.
After stripping out the existing electrical circuitry,..........
....... I created a wiring loom using a Deltang Rx65c, which I happened to have as a spare. My looms are fairly bog-standard, though this used two 14500 (AA sized) li-ion cells rather than my usual three 18650 li-ion cells. The cells were connected to a 3 way JST socket for balance charging and a 2S BMS protection board. Thence via a single-pole double-throw switch to a 2.5mm DC socket and to the Deltang Rx65c receiver/controller. The Rx65c is then connected to the motor, as shown below:
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| Click the image to enlarge |
The hole in the loco's dashboard in which the original DPDT switch was enlarged to take the DC charge socket, and another 4.5m diameter hole was drilled on the opposite side of the dashboard for the SPDT switch.
The 14500 cells were slotted into the cavity in which the original AA cells were located and the BMS board and Deltang receiver were nestled on top - all insulated with shrink-wrap tubing.
The loco was given a brief test-run to check all was working correctly before tackling the body-work.
The bodywork
At first, I thought I would just round the edges of the bonnet, add a few extra details and then repaint it .....
.... however, after looking online for a suitable prototype on which to base the conversion, I realised the bodywork more closely resembled an electric steeple-cab loco .....
...... than a self-propelled diesel. The only centre-cab narrow gauge diesel locos I could find had substantially taller bonnets. In the end, I opted for using this loco of German origin to provide me with inspiration.
To allow room for the arched bonnets at each end, I had to hack away at the existing bonnets. A few strokes of the razor saw and some tidying-up with a Stanley knife did the trick!
Using the dimensions of what remained of the bonnets as a guide, I designed and drew the parts needed for the new bonnets in TinkerCad.
The beauty of TinkerCad is that, as it's designed for kids to use, it's really easy to gain mastery over it. I've found other 3D CAD packages to be a lot more fiddly and frustrating to use. The limitation of TinkerCad is that it doesn't have as many bells and whistles as the more sophisticated packages, but I've found it is more than adequate for this sort of work.
I decided that, with some judicious hacking, I would be able to move the cab back by 15mm. The first job was to cut a 15mm slot in the sides of the rear bonnet.
After a fair bit of manoeuvring accompanied by an equal amount of cursing, I managed to separate the cab from the running plate. All credit to the designers of the kit - there were quite a few mounting lugs which needed to be sliced-through.
The cab was then placed in its new position and glued into place with thick viscosity superglue (I use Everbuild as provided by ToolStation).
The parts needed were printed out ......
.... and, at last, work could commence on the reconstruction.
The window frames were first attached.
Then the access doors were glued into place on the sides of the bonnets.
And these were then glued into place on the running plate.
As you can see, I applied filler to various gaps and also where my butchering had resulted in a few uneven surfaces. In addition, I masked off the cab with masking tape in preparation for its trip to the paint shop.
Painting and finishing
The body was then given a couple of coats of Halford's plastic filler primer from a rattle can.
Unfortunately, as can sometimes happen, the primer reacted badly with the original paint on the cab.....
.... which required a fair bit of additional filling and rubbing-down.
Incidentally, for sanding small areas of paintwork such as these, I use cheap emery boards from our local pound shop. They can be easily trimmed to fit into narrow spaces, and the board backing gives a smoother finish than emery or sandpaper alone would provide.
The loco body was then given another couple of coats of primer.
The finish was better, but there were still some minor blemishes and pockmarks which needed filling and rubbing-down further. Once this had been done, it was given another couple of coats of primer before being rubbed down again and a couple of coats of Halford's Rover Brooklands Green, the livery of my loco fleet.
Once the paint had dried and hardened off, name and number plates drawn in TinkerCAD and 3D printed on my resin printer were added, after they had been painted with red and gold acrylics.
New handrails were formed from 1.5mm diameter brass rod and inserted into the holes occupied by the previous handrails.
Before the roof was glued into place, resin cast details were added to the cab dashboard and a 3D printed driver was added (minus his legs which were carefully excised).
A cheap soundcard (from AliExpress) was wired-in.
The soundcard required a servo input and so this was connected to P8 of the Deltang Rx65c
This is a problem which I have encountered before with the Deltang Rx65 servo output (see Installing a Technobots programmable diesel soundcard with Deltang receivers ). I tried reprogramming one of the pads on an early Deltang compatible Micron MR603 to provide a servo output, but it failed. After mentioning this on the gardenrails.org forum, Andy at Micron contacted me and supplied me with a replacement receiver free of charge. Now, that's what I call service!
The output on the new MR603 was programmed for servo, and I'm pleased to report the loco and soundcard now perform slightly better. The engine note does rise slightly more than it did with the Deltang Rx65c but, because the top speed of the loco is reached with only a 1/3 twist of the speed knob, the servo signal doesn't rise very much.
The LED was connected to P1 of the MR603 via a 1k resistor to provide forward lighting.
