The Shay locomotive was a workhorse of the logging railroads of the mountains of West Virginia. It was one of three designs of gear-driven engines developed primarily for use on the steep, rough, temporary tracks of logging country. The boiler was off-center to the left, to balance the cylinders, crank-shaft, flexible shaft, and gearing on the right side, which drove the wheels, all of which were powered. This was a flexible, powerful, but slow locomotive, able to climb mountain grades of 10 percent and more.

Between 1882 and 1927, about 219 new Shays, weighing from 10 tons to 150 tons, were shipped from Lima Locomotive Works in Lima, Ohio, to West Virginia, more than any other state except Washington. West Virginia Pulp & Paper Company at Cass purchased 10 new and three used Shays, including more large engines (two 100-ton and three 150-ton) than any other lumber company in the world. Pardee & Curtin Lumber Company bought 10 new Shays, mostly 36-ton machines for its operations at Curtin on the Cherry River, the largest narrow gauge logging line in the state. On the steep coal mine branches in the New River Gorge, the Chesapeake & Ohio Railway used 15 huge 150-ton Shays, the most any major railroad ever owned.

In the early 1960s, the last working Shays were at the Ely-Thomas mill in Fenwick and in occasional use at Meadow River Lumber's operation at Rainelle. Eight Shays survive at the Cass Scenic Railroad, five of them operable and used to pull tourist trains up Cheat Mountain. Several from West Virginia are on exhibit in other states.

Other geared locomotives, made by the Climax and Heisler manufacturing companies of Pennsylvania, were used on West Virginia mountains. Climax engines were second in popularity only to the Shays, with 140 working in West Virginia at one time or another. Thirteen Heislers were used in West Virginia, including one in service today at Cass. The 70-ton Climax No. 9 was added to the Cass fleet in 2019, and another Climax is in service at Durbin.