Building a loco this size is a lot of work. I cheated a little, it's not live steam. It has a automotive starter motor and battery.
The drivers were from the locomotive that I posted a photo of in this thread.
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http://www.the-gauge.com/forums/showthread.php?s=&threadid=8481]
The pilot, trailing track and tender wheels are from small overhead crane trolleys.
Other than the frame almost everything is made of wood.
The boiler is a piece of heating duct, plastic flowerpots for domes, PVC pipe for the cvlinders and an old tachometer housing and flashlight parts for the headlight. The track in the photo is made from fence T-posts.
It ran when this photo was taken , (about 10 years ago) It is in need of a little maintainence now.