Breda LRV - Body, bogies and chassis

I can't remember the reason, but a while back I decided to make a model of a Breda LRV, from the San Francisco Muni light rail network. I rode on one of these when I first visited America, from underground out to the beach. They are an interesting vehicle, running on both underground subway-style lines, and running on the street.

So they have unusual features for a train, like indicators and side mirrors. They also have a high level floor for subway platforms, yet once they emerge into daylight and start running on the street, steps down to street level magically appear inside the doors.

Following the J├Ârgen Edgar technique, a not-especialy-accurate cutting plan was drawn up and transferred to clear styrene. A bit of scribing and cutting later and I had this:

1mm styrene pieces made up the ceiling and everything was glued together with regular Microscale styrene glue (the citrus scented stuff).

Getting the front angles right took a bit of work, and I made up some clear shapers for the inside of the cars to get the sides at the right angles. So far so good, nothing too complicated or fiddly, mostly just a bit repetitive scribing in all the windows.

Now the fun part. I needed a chassis for this thing. I had a Kato 11-105 motorised chassis for a B Train Shorty floating around that I'd never used, so I figured I'd use that. However that only provided two of the three bogies, and the bogies side frames it had were a little too wide, so I decided to make my own chassis using Kato bits.

First step, bogie sides. I ordered a 50 pack of 2mm pinpoint bearings, only to discover they were designed for HO and were far too deep for N scale. A quick pruning with my razor saw took care of that problem. I used some strip brass to make the sides and drilled holes for the bearings:

Then using the wheels from the Kato chassis, I carefully lined everything up and soldered on a piece of PCB material with two right angles on it:

This was fairly fiddly, I won't lie. A smarter person might use a variety of low temperature solders to join each piece together in turn. I however only have one type of solder and so everything tended to melt at the same time! I got there in the end though:

With just a little bit of tweaking I had some very freely rolling bogies, complete with all-wheel electrical pickups.

The central motor bogie was a little more work, as I needed to keep the multitude of small gears in precise alignment, while gluing on my custom side frames.

Alignment was very fiddly and came down to tenths of a millimetre, otherwise the gears wouldn't mesh smoothly.

I finished making the chassis and wiring up the bogies. Each end of the LRV pivots off the centre bogie, so far it has no trouble navigating 100mm radius curves. Some dismantled old laptops provided a useful selection of super miniature screws for attaching the various parts.

Close up of the centre bogie and pivoting arrangement:

Next I need to detail and paint the bodies, make the folding bellows between each carriage, and get the chassis running.

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Comments

Saturday, May 2 2015, 11:56 AM JD Lowe says...
That is very impressive work. I'm looking forward to seeing progress on this build. Excellent job!