Steam locos part 2.

'Are you sure we've got the right wheels on then?'

I've been doing a bit more thinking on this topic this weekend while making more beer.
Pretty much any six coupled steam loco from the 50's and 60's can be modeled using a basic chassis that is 5' + 5'. there were differences of a few inches either way, but this is only plus or minus 1mm. Likewise the wheels are really only 2 sizes; 48" and 54", again with a few inches either way. Walschearts valve gear is standard on all types. The cylinders are either Ab type, or Ww/Wf that look almost identical from a distance. Above the footplate, things improve markedly. All the pacific locos (including the Aa and Q's) wound up with Ab boilers in the 50's, so one size fits all. This means that for these classes the cabs and tenders are the only major bits of kit that need to be modeled. Ok, its not that easy, but far simpler than having to redo all the powered bits every time.




So what does this all mean. Basically, that with a generic set of parts, someone could make any 6 coupled loco for the late 50's and 60's. This includes the actual drive train, which in modern n scale style would have gearing on all axles with the rods just on for the ride. a 10mm diameter can motor would fit inside the boiler.

Now, what about wheels. The British 2mm association do some excellent work, but there is a problem. To do all the wheels for a 4-6-2 plus tender split frame chassis would cost you the princely sum of $158 at today's exchange rate, without any gears or frames. Doesn't really sound like a good idea does it. However a brass plated wheel on a steel 1/2 axle could be made locally, for what I would image to be a fraction of the cost. The coupling rods, crossheads and valve gear could be etched.

The 8 coupled J/K classes are similarly dealt with, as the wheel spacings are the same, and the only difference is the valve gear and cylinders. the wheels can be recycled from the project above. Bigger motors can be fitted due to the larger boilers being available.

It all sounds so easy doesn't it. :v)