English: Wheel on “Peggy,” a Lima Shay Geared Steam Locomotive (SN 2172).

In a geared steam locomotive, power from the cylinders was transmitted by shafts along the right side of the locomotive. The shafts turned bevel gears, which turned the wheels that rested on the rails. Left to right in this photo are a wheel, a bevel gear, a shaft, and another wheel.

This locomotive, named “Peggy,” is a Lima Shay geared steam locomotive. She was built in 1909 and worked in Oregon and Washington hauling timber out of forests. In 1933 all of the wood on Peggy was burned when she was caught in a large forest fire. She was rebuilt and continued working until 1950. During her 41-year career she hauled an estimated billion feet of logs.In 1955 she was donated to the City of Portland, Oregon. She was put on display, but was heavily damaged again in 1964 in a structure fire. She was restored from 1969 to 1971. She is now displayed at the World Forestry Center in Portland.Peggy was built by the Lima Locomotive Works in Lima, Ohio. As originally built she weighed 67,100 pounds. She is a Class B design with three steam cylinders, two trucks (sets of wheels), and eight wheels. More specifically she was a “Balloon” model with a working order weight of 42 tons. Originally she used wood as fuel, but was changed to burn oil early in her career. Her Shop Number is 2172.

Geared locomotives were invented by Ephraim Shay. By inserting gears between the steam cylinders and the drive wheels, using trucks that could pivot, and applying power to all of the locomotive’s wheels, he created an engine that could pull heavy loads but could also work on tracks that were less than ideal, had tight turns, and were laid on steep grades--common characteristics of tracks used for logging. Shay licensed his design to Lima Locomotive Works.