John, the asking price of a working steam locomotive is whatever the market will bear. A couple of the standard gauge rod locomotives on the market at the moment have an asking price in the range of $650,000. In the case of a Shay, the picture is more complicated because the mechanical complexity of the locomotive and the limited number of practical applications for such a machine. With the exception of certain mountain railroads such as the Georgetown Loop, a Shay is an interesting mechanical novelty, not a practical locomotive. For one thing, they don't go fast enough. Someone elsewhere in this thread commented how great it would be to see the three Ashby ex-West Side Shays running up the hill out of Chama on the C&TS. Well, you better have a whole day to do that (the West Side itself was about 65 miles long at it maximum; I was told by someone who actually made the trip that it took more than 16 hours to get from one end to the other--an average speed of a little over 4 m.p.h.!).
Another "marker" for the price of a steam locomotive is the cost of doing a Form 4 on the locomotive, something that could run as much as $500,000 (or more). So a $100,000 locomotive is no bargain if you have to turn around and do a Form 4. You skip doing a Form 4 at your own peril; if the FRA doesn't get you, your insurance carrier will! Doesn't matter these days if you are an insular railroad or a common carrier. In a court of law, it's called "best practices," and if you don't adhere to "best practices," you better have a darn good explanation for why you didn't.
So, that brings me back to your original question. How much is a Shay worth? To which I would say: How much are you willing to pay to own one? Everybody has their price.
As a side note, I can comment on what a sweet locomotive ex-West Side #14 is; I had the privilege of working in her cab for three operating seasons. Built like a Cadillac. As reliable as a house. Runs like a fine sewing machine. Fires so well that during the summer you struggle to keep it cool enough to avoid repeatedly blowing the pops. Will haul everything in sight. Couldn't ask for a better locomotive!
Mike
