South of the Northern Pacific, the original main line of the Union Pacific ran from Omaha up the Platte Trail through Cheyenne to Ogden, with a branch from Kansas City to Denver and Cheyenne. Between the main line and the branch the Chicago, Burlington & Quincy constructed a road that reached Denver in May, 1882. Here it met, in 1883, the Denver & Rio Grande, a narrow-gauge road that penetrated the divide by way of the canyon of the Arkansas River, and extended to the Great Salt Lake. The two roads together offered a competition to the Union Pacific for its whole length from the Missouri River to Ogden, and drove that road to extend feeder branches south to the Gulf and north into Oregon. Farther south the Atchison, Topeka & Santa Fe stretched the whole length of Kansas and followed the old trail to Santa Fe and the Rio Grande, and thence to Old Mexico. Its owners cooperated with the owners of the Atlantic & Pacific franchise, and the Southern Pacific of California, to build a connecting link between the Atchison, Topeka & Santa Fe at Albuquerque and the Colorado River at the Needles. From this point the Southern Pacific traversed the valleys of California. In October, 1883, trains were running from San Francisco to St. Louis over this road. [Illustration: By 1870 the railway net had covered the eastern half of the United States and had just begun its Pacific extension. There were 52,914 miles of railroad.] [Illustration: By 1890 the railway mileage of the United States had increased to 163,597, extending the railway net over the whole trans-Missouri region, and reinforced by lines in Canada and Mexico. THE WESTERN RAILROADS AND THE CONTINENTAL FRONTIER, 1870-1890 (Based upon the maps showing density of population in the Eleventh Rand-McNally Official Rail-Census, and upon Appleton's Railway Guide, November, 1871, and the way Guide, August, 1891.)] The Southern Pacific of California met the other continental lines at the Fort Yuma crossing of the Colorado River. The Texas Pacific had got only to Fort Worth before the panic of 1873. It now built across Texas toward El Paso. Subsidiary corporations owned by the Southern Pacific men built the line between El Paso and Fort Yuma, and enabled a through service to start to St. Louis in January, and to New Orleans in October, 1882. Yet another Southern Pacific line was opened through San Antonio and Houston, tapping the commerce of the Gulf shore, and running trains to New Orleans in February, 1883.