Union Pacific Railroad's Kelso Station was established in the Mojave desert of eastern California in 1905 when the San Pedro, Los Angeles & Salt Lake Railroad completed its line connecting Salt Lake with the west coast port of Los Angeles. Last passenger train crossed the tracks in 1997, freight is still transported on this line. The Kelso Depot Visitor Center of the Mojave National Preserve is now housed in the magnificent two-story Mission-style train depot, built by the Union Pacific Railroad in 1924 and now carefully renovated and preserved. Preserve Est. October 31, 1994 with the passage of the California Desert Protection Act. San Bernardino County, CA.