A compressed air turbine mechanical locomotive? My curiosity was piqued:

Hmm, there's a shop manual on this site:

http://www.narrowgaugechaos.com/RPC/Mat ... oIndex.htm

And there was another builder and type:

http://www.narrowgaugechaos.com/RPC/Mat ... TIndex.htm

The site this is from, narrowgaugechaos.com, also has some general pages for those of the industrial steam pot persuasion:

http://www.narrowgaugechaos.com/RPC/RPC.html

http://www.narrowgaugechaos.com/RPC/Mat ... cLoco.html

http://www.narrowgaugechaos.com/RPC/Mat ... mLoco.html

Like many of us, the fellow who runs this site is also a model railroader. One of his efforts is a steam-punky thing that would qualify as a cool April 1 entry:

http://www.narrowgaugechaos.com/VLIT/VLIT.html

Now, about your critics, and a possible attempt to stay "pure:" why not include a second section, an appendix, for "locomotives other than steam?"

What's interesting to note is that when I was making that abortive attempt to put together a large steam tourist rail network, my contact at MARC told me that the ICC regulations in effect at the time were essentially divided into two categories, "steam locomotives" and "locomotives other than steam." It was most ironic at that late date (early 1980s) that, based on what he said, an obsolete form of motive power was essentially still cataloged by the ICC as the primary form of railroad motive power, and what had originally been an experimental or secondary form of power with (originally) limited application (electric and diesel-electric locomotives) was still cataloged in what amounted to an appendix!

It was good for a smile at the time, and for me, still is. Steam Forever!

A little extra bonus here: this turned up in the search for material on the air turbine locomotives:

http://books.google.com/books/about/The ... lKAAAAMAAJ

Have fun.

It's your site, do whatever you feel is the best approach, and ignore the critics!

If it concerns you, maybe create a separate category for oddballs that aren't exactly steam, but are felt worth including?

Actually, the answer is embedded in code I wrote for the site a long time ago, and never fully implemented. The site has the capability (currently hidden) to create custom views of the data. I think I'm going to finish and deploy that. In that way, a user would be able to say that he wanted to see only standard gauge locomotives, no compressed air, and so forth. And as long as he didn't clear his cookies, each time he visited he would get the view of the data that he, himself designed. This might actually be fun to implement.
We shall see.

Doug, the site is great. Easy to use.

Thanks for updating the picture of DL&W 565. I like that pic. Soon we will have a nice pic of her on the turntable all dolled up and looking sweet!