'1:20.3 scale model of AG Price's 16 wheeler'
built by Ron Watson and Bill Mckenzie
I have a friend here in Auz that has helped with my layout at different times, and generally uses it as his own layout,
something I really enjoy, as I do enjoy his company and ideas. He's also been a good friend swapping parts and helping
to build different parts for each other. He's moved to 1:20.3 scale modelling in the last couple of years, and has detirmed
to build up a roster of geared locos for his logging roster. His ultimate goal is to represent at least one loco from all
the geared loco builder's world wide. So far he has done a great detail mod of a Bachmann Climax to represent the Puffing
Billy #1691 Climax, as it looks today, as well as 3 scratch built geared locos:
These being a 1:20.3 Dunkirk type B, a model of the 1926 Harmon (an unusual one-off geared loco from Melbourne Auz) and
this one, his best, a 1:20.3 scale model of AG Price's 16 wheeler, from 1912. AG Price was a large engineering firm in
New Zealand that built everything from their largest Pacific to unusual geared loco, of heisler design, as well as their
own contraptions, such as the 16 wheeler. Price is still in business today.
Ron scratch built the loco using styrene and brass details, along with the real wood for the NZ style cab. The trucks
are small Bachmann 20' freight trucks, with Tenmile spoked wheels. Bill McKenzie, another large scaler here, who is a real
nutter for mechanical design and is great when working with grears and brass, built the entire drive system for Ron's
model. All 16 wheels are powered via axle gears, with a diff that runs along the chassis like the prototype. The motor
is inside the tender, with a shaft running under the deck to the central/firebox area, where it then gears down to the
drive line. Its increadibly slow, powerful and really noisy! What a blast.
I'll soon put up a page on the 4largescale web site, with Ron's models. Ron's Dunkirk also features a full working 'V'
engine in the cab, with working valve gear and Johnson bar. The V engine was made scratch made and installed by Bill
McKenzie.
Anyway here it is for starters, the AG Price 16 wheeler of 1912, New Zealand, built by Ron Watson and Bill Mckenzie. This
is by far the most accurate model I've seen of this prototype, and works in a prototypical way.
Chaps,
The set up is really basic..two trucks mounted either end of a flat plate..the flat plate then pivots at it's centre
to the loco's frame. Two trucks form a single 8 wheel truck unit. Thats it, no more to it.
Now all the way through building this, we were concerned the lateral play of the inner most truck would be so wide, that no
universal running from the centre of the loco could keep up with the sway, not so, in practice, the lateral movements of the
entire mech is not that much at all. This thing can go round a 2ft radius, and the slip joints in the universals dont even
move that much. Unlike a Shay, which has the trucks at the far ends of the loco, and the univerals and slips along one side,
both contributing to large movement. On this, the 4 trucks are all close to each other and movement overal is not that
large. Once you get the driveline onto each twin truck unit, the moment from there on doesn't matter, because it's now on
the truck and not on the engine frame. Again since the two trucks on each unit are close together, not much moment between
them.
The reality is, this looks complicated, and hard to work out, but just build it as Price did, it works a treat and goes
around the tightest curves with no stress at all. Its difficult to build the drive line as Bill did, due to the large number
of gears and universals to go in. But in design, it's absoloutely simple...just hard to actually make!
