Denver and Rio Grande Railway

Denver & Rio Grande Western Railroad

Map of D&RGW and WP routes (ca. 1914).
Reporting mark	DRGW
Locale	Colorado, Utah, and New Mexico
Dates of operation	1870–1988
Successor	Southern Pacific Railroad Union Pacific Railroad
Track gauge	4 ft 8 1⁄2 in (1,435 mm) standard gauge
Previous gauge	and 3 ft (914 mm) gauge
Headquarters	Denver, Colorado

The Denver & Rio Grande Western Railroad (reporting mark DRGW), often shortened to Rio Grande, D&RG or D&RGW, formerly the Denver & Rio Grande Railroad, was an American Class I railroad company. The railroad started as a 3 ft (914 mm) narrow gauge line running south from Denver, Colorado in 1870. It served mainly as a transcontinental bridge line between Denver, and Salt Lake City, Utah. The Rio Grande was also a major origin of coal and mineral traffic.

The Rio Grande was the epitome of mountain railroading, with a motto of Through the Rockies, not around them and later Main line through the Rockies, both referring to the Rocky Mountains. The D&RGW operated the highest mainline rail line in the United States, over the 10,240 feet (3,120 m) Tennessee Pass in Colorado, and the famed routes through the Moffat Tunnel and the Royal Gorge. At its height in the mid-1880s, the D&RG had the largest narrow gauge railroad network in North America with 2,783 miles (4,479 km) of track interconnecting the states of Colorado, New Mexico, and Utah. Known for its independence, the D&RGW operated the last private intercity passenger train in the United States, the Rio Grande Zephyr, which was discontinued in 1983.