The fifteen-stall Lenzen Roundhouse was originally built in 1899 to serve the standard gauge San Jose-San Francisco rail commuter line and the narrow gauge South Pacific Coast Railroad, replacing two existing structures for those lines. The South Pacific Coast operated from Alameda, down the East Bay marshlands to San Jose, then over the mountains above Los Gatos on the way to Santa Cruz. Although the two railroads operated independently, both were early segments of Southern Pacific Railroad ownership. This roundhouse is unique because it was one of the few such structures built to serve two different gauged locomotives. The narrow gauge South Pacific Coast RR was converted to standard gauge by 1909.
Preservation of the structure thereby became the focus of the California Trolley and Railroad Corporation and other local interests. Recognizing the importance of this historic structure to its community, the Southern Pacific Railroad donated the building and turntable to Santa Clara County in 1994 for inclusion in a railroad museum. In 2000, the roundhouse was disassembled, palletized and moved to the county fairgrounds.
As the 101-year-old Southern Pacific Lenzen Roundhouse is dismantled for relocation, Union Pacific GP40 672 (ex-MKT 237; ex-CR 3111; née-PC 3111) pulls a ballast train past the old roundhouse. (San Jose, California – August 6, 2000)