Shay Geared Locomotive. Fig. 133.
A locomotive for climbing steep grades which utilizes the entire weight of engine and tender for adhesion. A three-cylinder vertical engine is mounted on one side just in front of the firebox. It drives a horizontal shaft made in sections and joined with flexible couplings, which extends the entire length of the engine and tender and drives all the axles by means of bevel gears on the shaft and wheels. The wheels are grouped in four-wheel swiveling trucks to enable the locomotive to round sharp curves.
Geoge L. Fowler, 1906