Thursday, 29 October 2015
Tuesday, 27 October 2015
Of the three northernmost cross-country railroads, the Northern Pacific had completed its mainline to the distant ocean by 1883, the Great Northern having finished its task in 1893. Meanwhile the Chicago, Milwaukee & St. Paul (as it was known then) had not ventured west of the Missouri River, but in 1907 that company's management authorized and extension (Chicago, Milwaukee & Puget Sound Railroad) to the Pacific's shores. Because there were very few suitable routes through the Rocky Mountains the CM & PS track lay close to that of the NP in western Montana, as well as in Washington State. The construction proceeded rapidly, and by the fall of 1909 the rails had reached Puget Sound. When it was completed the CM & StP/CM & PS became the second railroad to operate over its own track between the Midwest and the western sea, the Atchison, Topeka & Santa Fe system having been first.
The laying of rail over Pipestone Pass in Montana was difficult. The 14 miles between Butte and the tunnel was inclined at 1.8percent, while the eastern flank included nearly 24 miles of 2.) percent gradient. Both approaches were characterized by short segments of extreme curvature where deviations from the shortest route were needed to maintain a uniform grade. Pipestone Pass, however, was but one of four major summits which were obstacles in the path of Chicago, Milwaukee & Puget Sound. There was another almost identical one somewhat more than 100 miles to the east, s shorter one on the Montana - Idaho border, and the entire Cascade Mountain range in Washington.
The building of the CM & PS had been a bold move, completing as it did directly with the NP, as well as the GN and UP. The, at the end of 1915, it commenced electrified operations between Deer Lodge (West of Butte) and Three Forks to Harloton, Montana and westward over the Bitter Root Mountains to Avery, Idaho, 438 miles in all. During 1917-1919, 228 additional miles, between Othello and Tacoma, Washington, were strung with overhead wires, leaving a non electrified gap of 216 miles which still remains.
The overhead distribution system carried power at 3000V-DC, produced by AC-fed sub-stations along the line. General Electric and American Locomotive produced the locomotives, which were drawbar-coupled back-to-back pairs of 2-B+ 2000hp units. Each unit weighed 280,000 pounds, and could exert a tractive effort of 53,000 pounds. Subsequently, the paired units were separated, recombined and renumbered in 3, 4 and 5 unit groups. The 34A had been 10501A until 1939, and 10229A until 1932. GE's construction number was 5374A; Americans was 55948.