As the last transcontinental line to reach the Pacific, the Chicago, Milwaukee and St. Paul (as it was then called) had at its disposal in the first decade of the 20th Century a vastly different level of technology than was available to earlier transcontinental builders.

By 1909, limited electrifications for terminal and tunnel operations had been proved feasible elsewhere. At the same time, commercial demand for electricity was growing and the vast potential for hydro-electric power in western states was being developed. With this technology available, the possibility of electrical operation was considered as early as 1905 and 1906 while land for the extension was being acquired.

As they planned and surveyed the route, officials and construction engineers learned for themselves the benefits which electrification could provide. The long distances to Midwestern coal supplies, an abundance of hydroelectric potential close at hand, the long, severe winters and difficult terrain all underscored the advantages of electrifying.

As a result of these early considerations, parcels of land were purchased and set aside for possible electrical substations, and flow rights for generating dams were secured, all before the extension was completed.

But construction of the extension as a conventional railroad proceeded. Having the experience of earlier westward builders to draw on, and having the advantage of the Northern Pacific Railroad already close by to bring materials to work crews, construction of the extension proceeded remarkably well. Well-planned and highly organized, the 1,400-mile Pacific extension project was completed in slightly more than three years, from Glenham, S.D., to Seattle.

Limited operations were underway in some places in 1908 and the line was opened from Chicago to Seattle in 1909. However, the problems of operating steam locomotives year-round through the mountains in Montana and Idaho all too soon became apparent.

Steep grades, constant curvature and frequent tunnels made steam operation on the extension trying even in good weather. But long, bitter cold winters, bringing heavy snowfall and temperatures as low as 40 degrees below zero, compounded the difficulties. In cold weather, steam locomotives were extremely difficult to maintain, often suffered significant power losses, and sometimes simply wouldn’t run. Even in good weather, mountain grades and curves caused steam locomotives to lose a great deal of power.

The success of two other electrification projects in the Milwaukee’s territory brought further impetus for electrifying. In 1909, the Great Northern electrified its line through the Cascade Tunnel, and demonstrated the superiority of electric over steam operation in the difficult winter conditions. Of more direct impact was the highly successful electrification of the ore-carrying Butte, Anaconda and Pacific Railroad which connected with the Milwaukee. Watching the BA&P work out the problems of mountain electrification on a small scale, Milwaukee officials became certain that it could be done larger and better.



Years of the nation's  transcontinental completions:


1869 Union Pacific


1883 Northern Pacific


1893 Great Northern


1909 Milwaukee









Hydro-electric power abundant in western states












The nearby Northern Pacific Railroad brings materials













Operational challenges:

- steep grades

- constant curvature

- frequent tunnels

- heavy snowfall







The Great Northern electrified its  Cascade Tunnel



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Last Updated: March 03, 2009