Who invented the Shay geared steam locomotive?

Ephraim Shay invented the Shay geared steam locomotive. The Michigan lumberman and self-taught engineer wanted a practical way to move logs over steep, rough forest tracks, where ordinary steam locomotives could lose traction or derail.

Around 1875, Shay built a tramway for year-round logging and soon experimented with placing a steam engine on a flexible, trucked platform. His design transmitted power through gearing and a driveshaft rather than conventional side rods. That arrangement let the locomotive move slowly while delivering strong pulling power on sharp curves and uneven track.

Shay patented the basic locomotive concept in 1881 and licensed production to Lima Machine Works in Ohio. Lima built the prototype in 1880 and refined the design into the distinctive Shay locomotive used by logging, mining, and industrial railways. The name refers to Shay even though Lima manufactured most examples and other builders later produced related designs.