I recently re-read Sean McMullen's unique Greatwinter trilogy and was inspired to visualize the wind train described in the novels. The wind train engine is powered by a set of rotors to catch the wind. These can be raised or lowered into the car to control speed. A complicated rigging system holds the rotors vertical and balances the engine in high winds. This is an early image of the interior in development:

And an untextured toon render:

While the engine is described as complex with masts, booms, cables, the passenger cars are simple. Here are a couple of early toon renders:

Low quality render of partially textured wind engine: The engine has a working heliograph on the roof platform for signaling. There is also a set of operating wind instruments.

Neat idea, I'll have to read the book(s)

Do read them. I read the trilogy for the first time many years ago, and found they held up to my second reading this year. The first book, Souls in the Great Machine, is almost startling in tis originality. It's a very different post-apocalyptic novel depicting a society where "Dragon Librarians" hold the real power because the library, Libris, has maintained the knowledge of the past, but where disputes are settle by duels. Steam and electrical power are forbidden and Libris, has established a computer, the Calculor, that operates with human component. Through this all a mysterious "Call" periodically turns everyone into a mindless wanderer. In my opinion, the second and third books, which expand the world from Australia to North America and provide more of a back story, are not quite as good but I was intrigued by the characters and carried along nicely.

The wind train is imagined but it's imagined with actual historical parts. For instance, it incorporates wood-core Mansell wheels that were designed in the 1800s. Here are two renders of the Wind Engine with one side hidden. In the second the wind rotors are lowered into the engine.

Here's a render of the second class passenger car with the side hidden to show the interior. The seat backs flip to face rearward.

I'm still finishing some of the rigging.

Here's a fully-textured render of the passenger car:

And one of a 2-car train on the broad-gauge track:

Everything is pretty well finished now and into final testing and kitting.

The Wind Train uses a historically accurate broad gauge track developed by Isambard Kingdom Brunel in the 1800s. The gauge (or width) is seven feet vs. the standard four foot eight inch gauge. The Brunel railway is also distinguished by longitudinal running under the rails and tied together by lateral transoms with tie rods. The Brunel track looks very different from standard rail.

The Wind Train includes a set of morphing track with several kinds of roadbed.

The Wind Train is now in the Marketplace: