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7/8ths Inspection Car

by Chris Bird

Here is my story of a simple 7/8ths scale battery electric vehicle built on an HGLW basic power chassis. You can click on the images to see them large.


In my article on 7/8ths pen pot wagons (see index under 7/8ths scale on the left), I explained what can be done with a rather neat little bamboo pen pot (or box) available from the discount retailer Wilkinsons, here in the UK.

It started with some coal wagons:

Then progressed to an imaginary (and rather crazy) overseers wagon:

After I posted photos of this on the 7/8ths Lounge, Mike Brown suggested that it might make a rather neat inspection car if it were to be powered. This got me thinking....and the result is this:

In the world of the Summerlands Light Railway, back in the 1930's, they were in need of an inspection car and had the bright idea that battery electric was the way to go. With two large batteries in the rear compartment, they could get a range of at least five miles (though a lot less if the used the electric headlamp, converted from acetylene).

The HGLW Basic Chassis

Rather than construct a power chassis, I opted for an excellent little kit from the Houston Gate locomotive Works (www.hglw.co.uk). This is available in 32mm and 45mm for around £20. When it arrived, I downloaded and printed off the excellent instructions from the HGLW website and unpacked it all:

These are the main chassis parts ready to be glued up:

I used my modelling board, with some steel blocks to hold it all square. I used cling film to stop the superglue sticking the chassis to the board and then had to unstick the cling film! I think a rapid epoxy would have been better......

This is after the glue had set:

I used clips to hold the axle boxes while gluing (rapid epoxy) and it is essential to make sure they are correctly lined up with very little glue in the bearing hole.

Then, as I wanted to fit the axle boxes after painting, I masked up the chassis:

A few coats of primer and then, when thoroughly dry, a light rub down and green top coat. I made the mistake of using a spray enamel rather than acrylic car spray, so as I could not oven bake it (as I do with metal) it took a good 24hours to dry hard.

While it was drying, I etch primed the wheels and then gave them a brown finish using Revell acrylic "leather brown". Then it was a simple matter to fit the axles and bearings - remembering to fit the belt between axles!

Now I could epoxy the axle boxes into position:

The electric motor fits down through the hole, but I did not test it at this stage.

I then sealed any of the exposed MDF with dilute, waterproof PVA.

The Inspection Car

First I needed to extend the chassis so I used Wilkinsons bamboo plant labels to make a frame (though any strip wood would be fine).

This is a nice, snug fit on the power chassis:

Next I boarded the top of the frame with the same plant labels - and remembered that the frame length really needs accommodate a number of whole boards. I had to use a narrow one to fill the gap - but forgot to take any photos!

Then it was on to the pen pot. When I made the overseer's wagon, I used a jigsaw, but this was really a bit too violent, so this time I did straight cuts with a tenon saw and chain drilled the curves.

The fancy curved ends were inspired by the Penrhyn overseers coach, but at this stage I did wonder why I had bothered. However, those shapes did come in very handy later.......

I used a hole cutter to make a hole for the motor to come through, under a bench seat:

So then there was much sanding using the bench belt sander, a sanding drum on the Dremel and just plain sandpaper.

I made a curved front "box" from wood and bent some 0.5mm brass to match the curve using a piece of tubing. I also added the curved buffers which are faced with steel strip.

I did the same for the box at the back, using a matching curve. I soldered on two dolls house hinges which on the second attempt work well. On the first attempt, I soldered them solid! At this stage they just slip between the box and the deck.

This box is sized to take the two AA cell battery pack and a hole is drilled through for the wires .

I used four small screws to hold the superstructure to the deck and you can see here that I have added two rear supports for the bench seat.

The bench was simply made from a couple of spare pieces of the pen pot. The control stanchion is made from a brass fitting I found in my scrap box with a base plate and quadrant soldered on. I spent some time trying to find or make a suitable handle, but failed - so decided to come back to it.

You can also see that I embossed some dummy bolt heads with a nail punch. I found that just pressing it on gave a nice result without the use of a hammer. The sides still looked a bit plain though and I spent some time pondering on enhancing the axle boxes (of course 45mm ones would come further out).

So then it was on to the wiring. The key requirement here was to be able to get it apart, so I used simple terminal blocks - one in the battery compartment and one for the motor leads under the seat. The wiring plan - and I did need extra wire - is:

1. Original battery box wires to terminal block on back sheet.

2.  Wires from terminal block to switch, which was wired as in instructions to give forward and reverse. The switch fits through a hole in the seat.

3. The power wires for the motor go to the second terminal block and from there to the motor terminals.

The terminal blocks mean that I can easily remove the battery box and can remove the chassis/motor from below.

With the electrics sorted and tested, I decided to make some dummy plates for the side bars. These are just pieces of brass embossed with rivets. As they looked a bit too domed, I tapped each with a small hammer and then epoxied the plates in place. I used 16mm scale brass coach door handles on the front and rear covers, soldered in place.

Now it was time to take it apart for painting:

The base frame and deck was painted first using a little etch primer on the brass and then ordinary grey primer (and yes it does look a bit rough and ready underneath!)

The driver's compartment was masked up as I wanted it to show the wood inside:

It was primed

And top coated using Brooklands Green acrylic spray

The brass covers and stanchion were etch primed and sprayed, followed by an oven bake at 100 degrees C.

In this picture you can see the seat, which has a small semi-circular extension to cover the cut out in the base. As I could not get a strong enough butt joint, I drilled through and epoxied two 1.5mm OD steel pins to reinforce it. This allows it to be strong enough to hold the seat in place.

I also adjusted the position of the motor and glued it in position using a hot glue gun as suggested in the instructions.

Here it is assembled and looking very shiny. When I saw this photo I realised that it is important when using off cuts of the pen pots to make sure the good side is outside. See the side of the rear box (click on the image to see it large)!

I now had to return to the issue of the control handle to fit on the stanchion. As I couldn't find anything suitable, I filed on out of a piece of brass bar. Here it is as work in progress. Drilling the holes made a good guide for the shaping.

Here it is with the end of a fine paint brush used to make a wooden handle - and just before I re-soldered the spindle to straighten it!

A quick etch prime and some deep red paint completed it. I initially tried fixing it with double sided tape, but ended up drilling through from below the chassis, then marking the base before drilling and tapping 6BA. A long cheese head screw now secures all together.

It was starting to rain as I took this photo....

At this stage I felt that the front was a bit plain and so decided on a lamp. Luckily I had an old Mamod car lamp with a bright "brass effect" finish. I found that with the mounting screw in the back, it would slot perfectly into the V in the front board (and, indeed into the one in the back board).

I then masked the rim and sprayed it green. There is, of course, no logic to having an acetylene lamp on this ground breaking electric vehicle, so it was converted to electric......in my dreams......

Here is a photo showing the completed seat. It slots under the cross bar, which is glued to the bac sheet and then the single screw holds it down. The forward and reverse swithch really needs a dummy handle fitting......

And the side was a bit plain too - so I had a few very rough attempts at name plate etching. I had some rub down letters and so had a go at etching with Ferric Chloride. Let's just say I got a very 'antique' effect, but as a proper set would probably cost more than the whole loco, they will do for now. The name? Well i think you might have spotted the similarity to a certain item of church furniture....;-)

You might notice that I polished up the small handles on the front and rear boxes. Incidentally, the front is for the imaginary electric control system and fuses, and the rear, of course, contains the batteries.

Here is Pew with an early scratchbuilt coach and the overseer's wagon:

If you look at this image blown up (just click on it) you will see that the embossed bolt heads in the wood look very similar to the ones on the brass. The wooden ones have a tiny highlight of white on the top and a low light of black on the bottom.

It was still much too shiny though - so after a little rubbing down and touching up of some furry bits, I gave the chassis a very light weathering using a dilute brown/black wash with just a hint of white applied with an air brush. There is more to be done, but here the effect:

And here is a little video: