Utah Southern Railroad Extension

The Lynndyl Subdivision is a rail line owned and operated by the Union Pacific Railroad in the U.S. state of Utah, running from Salt Lake City southwest to Milford, where the Caliente Subdivision continues towards Los Angeles. It was formerly part of the Los Angeles and Salt Lake Railroad. The subdivision is named for Lynndyl, a small community along the rail line.

Mormon businessmen incorporated the Utah Southern Railroad in 1871 to build a standard gauge line from Salt Lake City south to Payson. It was built by the construction company Grover, McCune & Read, a firm owned by Alfred W. McCune and two other Utah businessmen. It was completed to that city and beyond to York (south of Santaquin) in 1875, and bought by the Union Pacific Railroad later that year. The UP organized the Utah Southern Railroad Extension in 1879, and completed the line to Frisco in 1880. Both companies merged with the Utah Central Railroad (Salt Lake City-Ogden) to form the UP-controlled Utah Central Railway in 1881, and in 1889 it was merged with the Utah and Northern Railway and other companies to form the Oregon Short Line and Utah Northern Railway, which was reorganized as the Oregon Short Line Railroad in 1897.