By popular request (well, one person anyway), I will occasionally post an article describing one of my earlier projects. This one is about my bubble car and its trailer.
If you think that this is to fill in when I don't have much to say about active projects, then I couldn't possibly commentâ€¦
The bubble car is the mainstay of the passenger service to South Yard (there isn't room on the layout for anything more). The model is 'based on' a BH Enterprises kit and a Kato chassis that I picked up from MG Sharp at the Warley show a few years ago.
I picked the Gloucester class 122 variant (without headcode boxes) for my model. There are some photos by John Vaughan of 55016 on the Looe branch on railcar.co.uk, so it's a reasonable match for my chosen period. This was a fortunate choice because Dapol have gone for the class 121, so at least my bubble car doesn't look the same as the off-the-shelf model. As far as I can tell, the trailer cars were nowhere near Devon or Cornwall by 1970, but the trailer was part of the kit so I modelled a Pressed Steel one that would have frequented the branches West of London.
BHE have continued the range of kits previously produced by Fleetline and MTK before them. At the time I bought it, I didn't know of any other DMU kits and the Dapol bubble car was probably not even a gleam in anybody's eye. I'd built several of these kits in the past, so I knew their strengths and weaknesses. The kits provide an opaque plastic floor, roof and clear plastic sides. There are etched overlays for the sides, moulded plastic bogies and whitemetal ends and underframe details. The kit provides no real help with fitting any kind of drive unit.
The whitemetal castings were hopeless in MTK days and they were still hopeless when I bought my kit, so they went in the bin without further ado. Most of the rest of the kit is quite reasonable, although the accuracy of the BHE floor mouldings was pretty poor on my example and needed remedial work by shaving with a chisel (the old MTK/Fleetline ones were better).
Having binned the end castings, I had given myself quite a lot of work to create some new cabs. These were made up from a solid multi-layer sandwich of 40 thou plasticard which was then drilled, filed and carved until the right shape was achieved. Quite a lot of work, but I was pretty happy with the end result. I also tried fabricating an end using some thinner plasticard and a sort of composite plasticard structure behind it to create the right shape. This turned out OK as well, so I used it on the trailer car. Since then I've discovered that Worsley Works sell etched DMU ends that would have saved me a bunch of effort. Such is life.
The Kato chassis was intended for some sort of Japanese railcar, so it had a nice low profile and partial mouldings of seats on top too, which was useful. I had to chop a few mill from each end to make it fit lengthways. Widthways I think I needed to shave some thickness from the back of the sides and I probably also cheated a little by setting the bottoms a little further apart than they should really be. The chassis uses a split axle design with pinpoint bearings. If memory serves, it also had traction tyres which meant that it wasn't a good candidate for the 2mm Association wheel turning service, so I had to improvise.
My re-wheeling solution involved the use of some very old 2mm Association coach wheels on 1mm axles. These have brass backs for most of their diameter with an insulating boss around the axle. I hammered some 5 amp fuse wire flat (and very thin) and soldered this to the back of the wheel. I then poked the end of it into the axle hole, pushed the axle in and then assembled these onto the Kato gear muffs. The result is not perfectly true, but it does the job.
The detail on the Kato chassis was filed away and representations of class 122 underframe equipment from plasticard were added instead. Likewise, the Japanese bogie detail was filed off and plasticard overlays added to produce something resembling a British DMU bogie.
Test running showed that the chassis was a little 'skittish' but could be calmed down nicely by adding some weight. The snag was that there wasn't anywhere to hide the weight so I wound up having to put a piece of lead sheet it in the roof space. This means that the centre of gravity is rather higher than I would like so the ride is probably a bit rock and roll.
One final bit of pain was attaching the etched sides. This is done after everything is painted, but from past experience I've struggled to find an adhesive that will fix brass to MTK or BHE clear plastic and is both neat and permanent. For the bubble car I used 24 hour epoxy. This has held so far, but judging the right amount proved very difficult. On one side of the trailer car I used too much and it oozed out onto the paintwork before setting. I have no idea how to rectify this so the trailer car now always presents the same side to the audience to hide my mistake.
The cab windows were flush glazed by cutting clear plastic sheet and gradually filing it to fit. This takes a lot of time but I don't know of any way to get better results. The trailer cab is still awaiting glazing and grab rails. I'll get around to it one day.
I couldn't find anything suitable for the 2 digit headcodes - these use a different (taller, thinner) font from the 4 character ones so I got hold of a free font editing tool on the Internet and created my own font by tracing around some scanned photos. This was then printed to the right size, sprayed with clear lacquer and stuck to the DMU with a frame made from 5 thou plasticard stuck on top.
So now I have a bubble car to run the passenger services to South Yard as well as occasional trips to the seaside on the branch service at St Ruth. It's quite easy to pick faults with it (there are plenty), but I'll gloss over that. It will probably be mistaken for an RTR model by some observers, but at least I know that it took a lot more time and care than that.