The museum's mission is to preserve the history of the Western Pacific Railroad and is operated by the Feather River Rail Society (reporting mark FRRX),[1] founded in 1983.

The holdings also include extensive corporate records and images, as well as personal collections from those who worked for the Western Pacific.

[3] Among the significant pieces in the WPRM collection are Western Pacific 805-A, an FP7 model passenger locomotive that pulled the California Zephyr;[11] Southern Pacific EMD GP9 #2873, nicknamed "the Kodachrome" by the volunteers, due to it being painted with the Kodachrome scheme from the failed Santa Fe–Southern Pacific merger; WP 2001, the first GP20 locomotive (an early turbocharged diesel);[12] WP 501, an early switch engine and the first diesel purchased by the Western Pacific; Western Pacific 0-6-0 steam locomotive 165, an oil burning switch engine built by ALCO in 1919; WP 3051, one of only two remaining GE U30B locomotives; WP 106 business car "Charles O. Sweetwood", built in 1917 and used during the Korean War as a rolling blood bank; WP 37, a 200-ton rail-mounted crane, two track clearing snowplows (one wedge type and one rotary); and several rare, early 20th century freight cars.

Also located at the site are the Portola Diesel Shop, built in 1953, and an interlocking tower from Oakland, California, currently stored unrebuilt.

The WPRM maintains several of their road diesels in mainline operating condition and has made occasional movements on Class I railroads using their own historic motive power.