Kelso arose as a railroad town because the Cima Grade was too long and steep for locomotives to pull trains without assistance and because reliable groundwater was available nearby. Helper engines supplied extra power and required a helper station with a roundhouse, a wye track, fuel, and abundant water for steam, first from springs in the Providence Mountains and later from nine wells. Built in 1924, the Kelso Depot contained a train station, ticket and telegraph office, restaurant, reading room, and dormitory rooms for railroad employees, and was often called the Kelso Club, a Union Pacific term for employee boarding and recreational facilities. During World War II, rail shipments of troops, tanks, and trucks through Kelso increased demand for helper crews and mechanics, while iron ore from Kaiser Steel’s nearby Vulcan Mine was loaded there for wartime steel manufacture, leading Union Pacific Railroad and Kaiser Steel to establish temporary housing for workers and their families. Kelso’s population declined after World War II as rail traffic fell and more powerful diesel engines no longer needed servicing there. As railroad technology advanced and additional personnel were no longer needed, the depot became obsolete, closed in 1985, and was saved from demolition by concerned citizens before being renovated and reopened as a National Park Service Visitor Center in October, 2005. From the mid-1940s to 1985, a two-cell strap-steel jail at Kelso held drunks and other unruly people for a night or two; originally west of the depot across Kelbaker Road, it was removed in 1985, kept in the backyard of Ron and Kay Mahoney in Barstow, California, and later donated by Kay Mahoney to the National Park Service when the depot reopened in 2005, while Richard Klepper recalled that before the jail arrived around 1944, the constable had used a reefer car as a jail.