High Quality Content by WIKIPEDIA articles! The Denver and Rio Grande Western Railroad (reporting mark DRGW), generally referred to as the Rio Grande, originally the Denver and Rio Grande Railroad, is a former U.S. railroad, originating as a narrow gauge line running south from Denver in 1870. In 1988, the Rio Grande's parent corporation, Rio Grande Industries, purchased Southern Pacific Transportation Company, and as the result of a merger, the larger Southern Pacific name was chosen for identity, marking the official end of the Rio Grande. The D&RGW served mainly as a transcontinental bridge line between Denver, Colorado, and Salt Lake City, Utah, and a major origin of coal and mineral traffic, with a motto of Through the Rockies, not around them. The Rio Grande was the epitome of mountain railroading, operating the highest mainline rail line in the United States, the over 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, around 1890, the D&RG had the largest operating narrow gauge railroad network in North America.