Eagle Mountain Railroad (EMRR) was a private railroad in California, owned by the Kaiser Steel Corporation, and is owned today by Kaiser Steel's successor, Kaiser Ventures, Inc. of Ontario, California.

The EMRR is 51 miles (82 km) long and is located in Riverside County, California. Constructed in 1947–1948, it was used until 1986 to haul iron ore from Kaiser's Eagle Mountain Mine in the Colorado Desert to an interchange with the Southern Pacific Transportation Company in the Coachella Valley. The last revenue train to operate over the line was on March 24, 1986.

The Eagle Mountain Railroad starts at a remote location called "Ferrum" (Latin for "iron") which is located adjacent to the Salton Sea in Riverside County, and terminates 51 miles (82 km) away at the Eagle Mountain Mine (also known as Iron Chief Mine).

The maintenance equipment shed at the Ferrum end of the Eagle Mountain Railroad.

Ferrum was the location of a five track yard that was used to interchange with the Southern Pacific Railroad. Also located at Ferrum is a wye (not disconnected) and maintenance equipment shed. The interchange yard parallels the present-day Union Pacific Railroad Yuma Subdivision main line, the main transcontinental railroad line between California and Texas. The main track heading to Eagle Mountain starts at the east end of the yard.

Upon leaving the Ferrum interchange yard, the track immediately climbs up a hill. Once reaching the top of the hill, the track drops down to a wooden trestle bridge. The track now heads east over mudflats while climbing a grade. There is also the wooden trestle bridge over Dos Palmas Wash. The track crosses over the rebuilt Coachella Canal. The canal passes under the track in a concrete siphon. The track crosses the now abandoned original channel of the Coachella Canal on a three span steel bridge. While the bridge remains, water no longer flows underneath.

The tracks continue climbing the mudflats east where they turned north on a sweeping curve. Continuing north, the tracks cross the Bradshaw Trail before passing through a small cut and entering the first of two horseshoe curves. After this horseshoe curve, the tracks run east along the foothills of the Chocolate Mountains while the Salt Creek Wash parallels the tracks on the south side.

After curving along the Chocolate Mountains for two miles (3 km), the tracks turn south and cross the Salt Creek Wash on the railroad's longest bridge. The "Salt Creek Wash Bridge" is 500 feet (150 m) long and 40 feet (12 m) high. The original bridge located here was a wooden trestle, but after a fire destroyed that bridge an all-steel bridge was constructed. After the bridge, the track enters the second or upper horseshoe curve. At the start of the horseshoe curve, the track is located on a high fill, but by the end of the curve, the track is located in a deep cut.

The tracks head northeast with the Salt Creek Wash paralleling the line on the north side. The tracks cross numerous small washes with either small wooden bridges or cast iron culverts allowing any water to pass. At Milepost 20, the uphill grade remained at a constant 2.0% ever since before Milepost 4.^[1]

The railroad reaches the top of the long climb from Ferrum at "Summit", which is located at Milepost 25.^[1] A 3,000 feet (910 m) long passing siding and a short storage spur are located here. A maintenance shed is also located here.

After Summit, the track begins a long down hill run that will go almost the entire way to Eagle Mountain. Just past Summit, the tracks turn north and head towards Interstate 10. Just prior to crossing under Interstate 10, there are three small maintenance sheds. The "Interstate 10 Underpass" is located at the Red Cloud Road Exit. After the underpass, the tracks curve east and start running along the foothills of the Eagle Mountains. At Milepost 35.8 is "Entrance", the location of a short 450-foot (140 m) storage track. Shortly after Entrance, the tracks curve north again and head for the Victory Hills. Just before arriving at the Victory Hills, the tracks cross Eagle Mountain Road, the original access road to the mine. This is the first paved road (other than Interstate 10) that the railroad has crossed.

The Victory Hills are a chain of small hills that run east of the Eagle Mountains and provide a minor obstacle to the railroad. The railroad passes through these hills by going through a deep cut in the low part between two hills. After crossing Eagle Mountain Road for a second time, the tracks arrive at "Tele Pass". The railroad today passes between the same two mountains. Tele Pass is the end of the downhill grade from Summit and for here to the mine is all uphill.

The uphill climb from Tele Pass to the Eagle Mountain Mine is called "Caution Hill" and is so named because its 2.15% grade is the steepest on the line and descending it with a loaded ore train required great caution. It got its name after a loaded train ran away here in the early days of the railroad. All loaded ore trains descending Caution Hill were restricted to 15 mph (24 km/h) and were required to come to a complete stop at the bottom for 5 minutes to cool their brakes before proceeding. During the climb up to Eagle Mountain, the tracks cross Eagle Mountain Road for a third time and then cross Aqueduct Road. Immediately after Aqueduct Road, the railroad crosses an underground section of the Colorado River Aqueduct. Fears that vibrations from the heavy trains would damage the underground concrete aqueduct, the railroad crosses the aqueduct on a 50-foot (15 m) steel bridge. While this bridge appears to cross over nothing since the desert sand covering the aqueduct covers the lower part of the bridge, its does serve a vital function. As the tracks approach Eagle Mountain, they cross Eagle Mountain Road for the fourth and final time before looping around the base of the mountains and arriving at the Eagle Mountain Mine.

"Eagle Mountain Mine" is located at Milepost 51.0 with the end of track located at Milepost 51.3. There are four long tracks used in the loading ore process located here, along with a two track maintenance shop, a wye, and a few storage tracks. All the railroad facilities are located immediately west of the Eagle Mountain townsite.

Kaiser Steel Corporation was incorporated on December 1, 1941, for the purpose of manufacturing steel in Southern California. The finished steel was needed to supply the various shipbuilding facilities controlled by Henry J. Kaiser on the west coast. These facilities were building ships for the British government and were using costly eastern steel that was in short supply. After obtaining the $125 million needed, construction of the mill in Fontana, California, began. In August 1943, the first plate steel rolled off the production line at the Fontana Mill.

Coal for this early production came from Utah Fuel Company Mine No. 2 at Sunnyside, Utah, and was transported to the mill via the Union Pacific Railroad. In 1950, Kaiser Steel purchased the entire Sunnyside, Utah facility. In 1955, Kaiser purchased 500,000 acres (2,000 km²) of land near Raton, New Mexico, for future expanded production. The existing mine at this Raton location, named the Koehler Mine, was operated and upgraded until a newer and more modern mine could be completed. This new mine, named York Canyon Mine, served as the major source of coking coal until the Fontana Mill closed in 1983.

Also needed for the production of steel was limestone. Until 1955, this material was purchased from various sources in California and Nevada. In that year Kaiser Steel purchased a large deposit located at Cushenbury, California, only 75 miles (121 km) from the Fontana Mill. The limestone was transported to the Fontana Mill by the Santa Fe Railway.

The last ingredient needed for the steelmaking process was a reliable source of iron ore. Kaiser Steel purchased the Vulcan Mine located near Kelso, California, which served as the primary source of ore until 1948. The Union Pacific Railroad transported the iron ore from Kelso to the Fontana Mill. This ore, however, was not of good enough quality to satisfy Kaiser and a better source was sought. In 1944, Kaiser Steel purchased the large Eagle Mountain mining claim from the Southern Pacific Railroad and began development of the Eagle Mountain Mine after the end of World War II.