Like many innovations, the Shay locomotive was invented by an entrepreneur trying to get a jump on the competition. When Civil War veteran and ex-schoolteacher Ephraim Shay opened a sawmill in Michigan in the 1870's, logging was largely a winter operation. Roads made of ice and snow enabled lumberjacks to bring timber to mills with horse-drawn sleds.
Shay reasoned - correctly, as it turned out - that laying rails through the woods would allow him to supply his mill year-round and undercut his competitors' lumber prices. Horses, Shay's original motive power, proved problematic as they tended to get run over by log cars on downgrades. Shay experimented with a small steam engine but the pounding of the side rods was too much for his light temporary track. The lightbulb moment came when he noticed that his flatcars, however, were not tough on the track, and he decided to power a flatcar with a steam engine and a belt drive to one axle. It was several years later in 1880 that machinist John Carnes at the Lima Machine Works, while modifying a locomotive for Ephraim Shay, came up with the idea of powering all trucks with a drive shaft and beveled gears. Within a few decades, the re-named Lima Locomotive Works was one of America's Big Three steam locomotive builders.
Of the 2,770 Shays that Lima produced, only six were built after 1930. By 1944, when the Western Maryland ordered a massive 3-truck Shay to serve a Maryland coal mine, few Lima employees remembered how to build one. Shop crews preferred working on more familiar engines for the war effort, and it took a year to construct WM No. 6. What turned out to be the last and nearly the largest Shay ever built worked just four years before the mine closed and she was retired. Fortunately, one of the nation's first railroad museums opened nearby just a few years later, and No. 6 became the WM's contribution to the B&O Transportation Museum in Baltimore. Even more fortunately, No. 6 was later traded to the Cass Scenic Railroad in Cass, West Virginia, where she steams in tourist service today.
The M.T.H 3-Truck and 4-Truck Shay reappears in the 2023 Premier Line fully detailed with digital sounds recorded from the actual engines used at Cass including the correct six chuffs per drive shaft revolution. Few, if any, previous O gauge models have duplicated the rapid-fire exhaust notes that make a Shay at crawl speed sound like it's going a hundred miles an hour. The combination of DCS and Proto-Sound 3.0 allows this model to portray the slow speed theatre and tremendous pulling power that marked Ephraim Shay's invention.