What we need is a BIG Diesel

What we need is a BIG Diesel
Victoria on 'Thunderbird' duties 2011 Santa Specials
Victoria on ‘Thunderbird’ duties 2011 Santa Specials

Written by Martyn Redfearn and Brian Biggs

It all started when we ran the first Santa Special at Brighouse and Halifax Model Engineers. It was my idea to run the Santa Specials and I did all the planning, which included a 10 minute timetable. No problem, the two largest locos should easily cope, but what would happen if we lost a loco? “What we need is a big diesel!”

We started to think it through and the main thought was to keep it simple, scrounge or buy off the shelf (Ebay) as much as possible. One aim was unlimited running which ruled out batteries, so Brian suggested a proper diesel electric, using a single phase generator feeding 3 phase motors through digital phase converters. So the Ebay hunt was on.  First, we needed to target a multi-cylinder diesel generator. We bought fairly cheaply a 6KVA 220 volt twin cylinder diesel which Brian completely stripped and serviced.

The prototype was an 18″ gauge locomotive.

I happened to have the remains of a failed project to build a very large 7 ¼” gauge 2-8-0 0-8-2 narrow gauge Garratt (it would have been 21’ long and 27″ wide). Brian got underway with the first task, a bogie (a “truck” in America). I adapted the drawings I had of the Garratt from 2-8-0 to 0-6-0. Our thoughts on body design went through many phases with both English and American prototypes being considered. Ultimately we kept coming back to Carnegie, which was the second loco in the Hunslet series of 18″ locos for the Woolwich Arsenal (the first being Albert), which gave our project her name.

The first version.

The Garratt was 27″ wide across the buffers’ beams and there happened to be 4 pieces 27″ x 10″, so Victoria ended up 27″ wide with 10″ buffers. This steel determined the overall size of the loco. About this time the most fantastic design tool came my way, 3D drawing software, which I used to sketch Victoria (left) in order to make sure everything would fit. It also meant I supplied Brian with some interesting measurements, 9.97561mm instead of 10mm. I should say Brian likes metric, but the Garratt bits were all imperial which is what I was drawing in.

Brian complained about the amount of cast iron dust from the 12 wheels, mind you nothing is small on Victoria. The castings weighed 15kg and 11 ¼” over tread. Two further wheel castings were turned down, about 9″ diameter to use as disc brakes. These are air operated using car brake pads.

Brian setting the controller plugged into the mains.
Brian setting the controller plugged into the mains.

Ebay was again the choice for motor and phase converter plus loads of electrical bits. With two bogies completed we temporarily mounted the generator on one bogie with the motor and controller on the other, then headed off to the track. Run number 1 on Youtube. First moves were promising, but then the controller cut out. Brian tried numerous settings, but he soon realised that the problem was the generator. It could not keep the voltage in the range required for the phase converter. Back to Ebay and a new digitally controlled generator was purchased.

Next was the main chassis which was my project. I cobbled together some scrap heavy gauge galvanised tubing, 3 pieces per side. Then we tried test run number 2 with the new generator, but this time with the generator on the chassis and only one powered bogie. Run number 2 on Youtube. Brian complained about the number of different settings on the phase converter, but he got it to work eventually. So it was back to Brian’s workshop, well garden, to mount the generator, seat and framework to hold the bodywork in position.

With the generator mounted and motors on both bogies we could work out exactly where the seat could go, but how did that compare with the 3D design? Surely, I knew where the seat was going. Well, if you compare the photos and the 3D drawing, the motors are not where they were drawn. The seat was a little higher than I had planned, so the next problem would be cab height. I measured the loco shed at Brighouse and redesigned the roof for a ‘close fit’.

The second version with upgraded generator.

I promised to sort out the bodywork and, with limited time, called for expert help. By now, Victoria was in the engine shed at Brighouse and Halifax Model Engineers. The bodywork is all done in 2mm aluminium alloy. Now one thing I did not think about was the curved track just before the shed door. The result was a roof that hit the arch, so half an inch had to come off the height.

BHME’s May 2009 opening day was a little wet and quiet, so Simon and I took advantage of this to press on with the cab and roof which were temporarily bolted onto the chassis. With some insulating tape holding the bonnet together we ventured out into the rain to pull the last train of the day. 6 coaches, plus guard’s van, were pulled round without problem and we had people waiting in the rain to ride behind her.

During the build Brian had purchased a CNC milling machine. I thought the best way of testing it out was to send him some 3D drawings of name and makers’ plates so that they could be CNC’d out of brass. The maker’s plates are based on the original Hunslet plates, with a touch of ‘Huddersfield Corporation Transport’ style, which gave us the B at one end and the R at the other.

To fit the dashboard we had to remove the spectacle plate which also needed shortening –  remember somebody got the body ½” too high. Also, guess who had riveted the spectacle plate? We did use rivet nuts and 4mm machine screws everywhere that we thought panels might need to be removed.

When the louvered bonnet panels arrived we decided to fit the sides as in one sheet rather than the 4 separate panels. Now we found out that things in front of the cab were not as square as they should be. There was no way the very square panels would go on without some work. Of course, a professional would have lined up the centreline on the bonnet with the centre line on the cab before drilling holes. We tried one side first and couldn’t work out why there was a gap. Then you guessed it – the centre line showed the bonnet was too far over to the other side! Hidden under the bonnet is a full size chime whistle I bought via Ebay from America. It does use rather a lot of air, but sounds wonderful. The prototype was also fitted with an air operated whistle.

The painter (Ray) requested that the panels be removed for priming and then replaced for the top coat. Ray was very specific that we had to drill all the holes before he got going with the spray gun, now did we fit ….. or ….? The colour scheme was left to me. In my view diesels need to be bright and I suggested the ‘Huddersfield Corporation’ trolley bus colour scheme of red and cream. Huddersfield did run electrically powered goods wagons over their tramways, so it seemed to be a good idea to me. No doubt you will either like it or hate it, but I love it.

We had been invited to put Victoria on the 7 ¼” Gauge Society’s stand at the 2011 Harrogate Exhibition, so the race was now on to finish her in time. Ray did a great job painting her outside in some pretty cold weather. Victoria seemed to attract a lot of interest particularly from the younger visitors and from locals who were trying to work out if there ever was a full size loco in that colour scheme. As we got a number of children’s parents asking if they could sit inside I decided it was time to switch the compressor on and let them blow the whistle. It was fun watching as people tried to work out where the chime whistle was coming from.

Victoria is a regular runner at Brighouse and Halifax Model Engineers open days, see www.bhme.co.uk for details. Now we have a big enough trailer and hope to be visiting other UK 7-¼” railways this year. Here are more photos.
Major Dimensions

  • Width 27″
  • Length 8’ 3″
  • Height 56″
  • Weight ¾ tonne (estimated)
  • Power 2 x 1hp geared down 16 to 1
  • Top speed set at 6mph (this can be adjusted in the software up to a maximum of 16mph!)
  • Air – main 100 psi – brakes 60 psi.