Ephraim Shay, an American lumberman and amateur mechanical engineer, was born July 17, 1839. In the 1870s, Shay was settled in northern Michigan, running a store and a small logging operation, and faced with the problem of getting logs to his sawmill. Few logging operations used tramways or railways, because they were dangerous to horses. If you tried to use a steam engine, you had even more problems, because the locomotives available, with their huge drive wheels and alternating piston rod action, tore the winding rails apart.
So Shay invented his own locomotive, a strange-looking machine, like a flat-car with a boiler on top, and not centered, but off to the left, because the right side had several large pistons that went up and down. The pistons were connected to a drive shaft with flexible couplings that ran along the right side of the wheels – small wheels, which received power through a series of bevel gears (first and third images). The advantages were that all the wheels were drive wheels, and there was no rocking side-to-side motion, so there was much less stress on the track.
Shay had one built by the Lima Locomotive Works in Ohio in 1880, found that it worked just fine, patented the mechanism in 1881, and Shay locomotives started selling, slowly at first, and then by the score. By 1900, there were thousands on the job, mostly in the employ of loggers, but other uses were found, since a Shay has exceptionally good traction, and can negotiate very tight curves. In 1914, our own Kansas City Southern bought two Shays to use in its switchyard; one of these was rated for a 130 ton load, the other a whopping 160 tons.
The last Shay locomotive was built in 1945, but there are many still around on tourist railways (fourth image) and in railroad museums (fifth image). The Cass Scenic Railroad Park in West Virginia sits on the site of a former logging railway; it still has 8 of the original Shays in operation.
There is also one serving on the historic Georgetown Loop Railroad in Colorado, west of Denver; there is a video of the engine in operation on YouTube, with some nice close-ups of the outside pistons and gear train, which is what makes a Shay so distinctive (the Shay is running in reverse in the video, so you are looking at its right side, not its left. Hardly anyone films the left side of a Shay).
Shay the man became quite wealthy from his patent royalties, and he apparently did not run out of ideas, as he later built himself a hexagonal house in Harbor Springs, Michigan, fabricated entirely out of sheet metal, stamped to look like wood, brick, and mortar. It is still there, and listed on the National Register of Historic Places, should you find yourself on the northern tip of the southern peninsula with some time to spare (sixth image).
Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City. Comments or corrections are welcome; please direct to firstname.lastname@example.org.