The Chief Engineer and Engineering Files series (1903-1972) contains materials relating to the Chief Engineers office in Los Angeles, California. The chief engineers office was responsible for all railroad construction, including track, sidings, stations, depots, and all railroad and railroad-owned buildings. The chief engineer laid out the company townsites in Las Vegas, Nevada and designed the depots. The Engineering Department was also responsible for the construction of all water facilities and pipelines in Las Vegas, as well as any other towns in which the railroad owned the water supply. The local engineer in Las Vegas reported to the Chief Engineer in Los Angeles. During World War II, the engineers office was responsible for protecting critical railroad installations for which there is a series of files titled “War Conditions."

The Industrial Development series (1914-1967) contains files for the development of industrial properties on railroad-owned land in Nevada towns outside Las Vegas, including Boulder City, Henderson, Logandale, Pioche, Panaca, and Overton. Industrial development files for Las Vegas are included in the Las Vegas Land & Water Company series.

The Land and Tax series (1891-1974) contains files for demountable houses in Las Vegas built between 1943 and 1961; company houses in Caliente, Nevada; leases and agreements; general correspondence, acquisitions, and “vacations” (when the company vacated properties); and land valuations.

The Publications, Field Books, File Indexes, and Code Books series (1901-1960) contains survey field books, articles of incorporation, code books, and indexes to the company files and filing system.

The Bound Legal Briefs series (1913) is comprised of sixty-one volumes of legal cases filed in the California Judicial District by the Union Pacific Railroad Law Department.

The Blueprints and Drawings series (1902-1975) contain drawings and maps of railroad buildings including depots in Nevada, Utah, and California; employee cottages, houses, and hospitals; and other railroad operational buildings, maps, and surveys. Also included are drawings of plats of track, right of way, elevation, easements, highways and roads, water facilities, and pipelines. The types of drawings include blueprints, blue-line, brown-line, tracing paper, vellum, mylar, and linen. Architectural drawings include site plans, floor plans, elevations, roof plans, sections, and schematic details. Structural drawings include foundation details, framing plans, and structural connection details. Mechanical drawings include plans detailing air conditioning ductwork and machinery schematics.

This series also contains sets of original drawings by architect Gilbert Stanley Underwood for the lodges and other park buildings at the Southern Utah National Parks at Zion, Bryce Canyon, Cedar Breaks, and the North Rim of the Grand Canyon constructed between 1924 and 1928 by the Union Pacific Railroad and the National Park Service to develop resort facilities to enhance tourism and the railroad's passenger service.

The General Manager, Manager of Properties, and Manager of Industrial Development in Los Angeles, California sub-series (1900-1976) consists of information related to the physical development of Union Pacific railroad towns and sites outside of Las Vegas, Nevada, including Yermo, California. Files include building leases, sales and purchases of land and water, accounting and other business practices, legislative matters, and industrial development along the Union Pacific rail routes.