Thats funny, I own one of his Southern Ry. Transfer Caboose's that I purchase at a model RR show a few months ago. http://www.smokymountainmodelworks.com/ho.html

I was looking at his Rapid Prototyping -- Custom Urethane Castings portion of his website. Looks like pretty cool...
http://www.smokymountainmodelworks.com/rapid.html

Some Snippits
Quote:
We build parts using time-tested, Somos resins. The 7100 resin is an amber-colored, rigid material used for sturdy models and RTV, plaster-cast mold patterns and investment patterns. Clear resins are also available.

Quote:
Urethanes are available in durometers from 10A to 90A (soft) and 50D to 85D (hard) and in several colors, including UV-resistant clear, translucent tints and glass-filled, high-temp, D-scale durometer urethanes for premium strength.


Quote:
SMMW also makes silicone reproductions. This material is recommended for projects that require contact with skin (many urethanes exude release agents that can cause skin irritation; silicones are more inert)...


Sean in NC