The first successful rotary snow plow was designed by Canadian Orang Jull, who hired the Leslie Brothers to build the first model, with the first tests conducted in the winter of 1883-84. The Leslies soon purchased the manufacturing rights and built Leslie-type rotaries, producing 64 plows between 1885 and 1903 before selling the rights to the American Locomotive Company. From 1905 to 1937, the American Locomotive Company built 71 more plows, including SPMW 7221, which was built at the ALCO Cooke Locomotive works in Schenectady, New York, in 1917 and delivered later that year to Southern Pacific Railroad in Sacramento. To clear snow from the rail, a rotary plow had to be lowered off its wheel assemblies, known as trucks, and during operations the bottom of the plow rode 3 inches above the top of the rail. Rotaries were originally powered by a steam locomotive engine driving a ring and pinion system. In 1966, SPMW 7221 was converted to electric power to turn the blade and was renumbered SPMW 221, following the practice used for all rotaries after electrification. It was stored in Roseville for many years and maintained for heavy winter storms over Donner Summit, a key east-west corridor for moving freight and passengers. Union Pacific last operated SPMW 221 in the 1980s, and it was donated to the City of Roseville in 2014.