High Quality Content by WIKIPEDIA articles! The Denver Rio Grande Western Railroad (reporting mark DRGW), often shortened to Rio Grande or D RGW, formerly the Denver Rio Grande Railroad, is a defunct U.S. railroad company. The railroad started as a narrow gauge line running south from Denver, Colorado in 1870; however, 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.