It was only 1 of a total production of 4 of that particular model. Might explain the high price.
I think Dan Glasure and Brasstrains has done more to revitalize the brass train business (mostly HO) that anyone in the past 20 years. They extract top $$$ out of anything they sell and the more rare the higher the price. I'm sure most is due to their worldwide exposure and professional manner. I had my doubts when they started up this venture, but you can't argue with success.
BH