David_T wrote:
Since the Kozo Shay is standard gauge, if you rescale it to F (1' = 15mm), it would make a nice locomotive. The problem I see is when you put the 3' (45mm gauge) narrow gauge trucks under it. This will be too much mis-alignment between the engine shaft (standard gauge locomotive location)and the truck gear shafts. I figure about 10mm. In the plans there is about 1mm offset for the standard gauge loco. The Heisler and Climax do not have this problem. I would suggest some research of prototype NG shays and see how they handled this issue.
I've only see the opposite situation, where they slope outwards to accomodate standard gauge on a smaller locomotive.
For narrow gauge, if you have a boiler that's too big you have to offset it more (messing up the balance) to get the cylinders inwards enough. So it's probably a careful compromise between boiler diameter, offset and cylinder placement.
Here are a few pictures I found with some examples of cylinders sloping outwards to the shaft line for NG to standard gauge. I suppose you could do this in reverse, sloping inwards.
The Heisler is the easiest geared engine to convert gauges back and forth, I believe there is someone out there with an engine that has two sets of trucks, one for 4 3/4" and one for 7 1/2" gauge.
And do check out Ed Hume's pics. He did a stunning job on the Heisler and Climax in Gauge 1 using the above described conversion technique.
I am not sure but he might be doing the Shay as well, haven't talk to him in a while. Ed and I went to Japan and visited Kozo several years ago.