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< Short time project >

5 inch gauge becomes the mainstream in Japan recently. So I have little chance to drive 3 1/2" William. Also I guess it takes ten more years to complete 5" C53. Therefore I decided to make another 5" gauge loco that will be finished shortly. Necessary conditions are as follows.

- Prototype: 0-4-0 small loco
- Final weight: 70 to 80kg
- Using laser cut parts and Modela-made wood patterns
- Outsourcing boiler
- Using O.S. fitting parts
- No super heater

I chose Alice class Hunslet as the prototype. There is famous 5" Hunslet of Don Young design. I referred boiler design from it. Other components are designed from full scale dimention.

I got a book of the Hunslet that contains drawings and many photographs including disassembled condition. In four months oversea business trip, I had finished designing of the loco. I utilized 3D-CAD "Alibre Design" for the work. I think 3D-CAD is not necessary for model locomotive designing. But it is vital for me because I have to make wood patterns by Modela with 3D-CAD data.

The valve gear is Stephenson type made from laser-cut parts. It is advantage of this kind of locomotive that we need not finish edges of the parts because all of the valve gear components are hidden between the frames.

The picture shows horizontal arrangement of the motion parts. Wheels and valve gear are between the frames while the crank pins are out of the frames. The color variation of the picture shows kinds of material as follows.
Gray = steel / Yellow = brass / Dark yellow = gunmetal / Pink = copper / Blue =

The cylinder block consists of outside cylinder part and inside steam chest. As the piston axis is far from the valve axis, the cylinder block is very long in side direction. It is the same design as the prototype. The bar between the cylinder blocks shows driving rod for axle driven pump.

All of the cab components are except the regulator. First of all, I bought the parts and measured to prepare 3D data. The regulator is simple screw type. The steam dome and safety valves are in the cab. Steam from the safety valve is exhausted over the roof through two pipes on the safety valves. It is the same as the prototype.

The boiler is designed similar to the Don Young Hunslet, because I plan to outsource the boiler to UK supplier. The loco doesn't have super heater, so the boiler doesn't have large fire tubes.

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