The Swayne Lumber Company operated a saw mill 1,800 feet above the trackage of the Western Pacific in California. They had a total of four 60-ton three-truck Shays, three of which had been built directly for this company. Although they differed in details since they had been built over 15 years, their main dimensions were the same. So all had a boiler pressure of 200 psi, 32-inch drivers and cylinders which were eleven by twelve inches. All were oil burners with 2,000 gallons of water, but their tank capacity was either 1,000 or 1,200 gallons. 

No. 4 had originally been built for the Truckee Lumber Co. in July 1911 with works number 2465 and was bought by the Swayne Lumber Co. in May 1912. It already left Swayne Lumber Co. and came to West Side Lumber Co. at the same time when the company ordered the first locomotive of this type new. Number 3, later 1, was delivered in August 1917 and carried the works number 2926. It was wrecked in 1924, but rebuilt in 1928. The second No. 2 was delivered in April 1920 with works number 3078. No. 6 was delivered in April 1926 and carried works number 3302.

The three remaining Shays received piston valves in 1929. They were sold between 1939 and 1942. While 2 and 3 came to the Michigan-California Lumber Co., 6 came to the West Side Lumber Co. in 1940. Today it can be found in the Colorado Railroad Museum. No. 4 ist still operational today with the Roaring Camp & Big Trees Narrow Gauge Railroad. It carries the number 7 and the name “Sonora”.