The Milwaukee Road Bi-Polars, Class EP-2

The Milwaukee Road’s Class EP-2 electric locomotives, commonly known as Bi-Polars, were one of the most interesting designs ever developed. Arriving just a few years after the EP-1s, the Bi-Polars, built exclusively for passenger service, were another collaboration from General Electric and the American Locomotive Company (Alco). Not only was this design one of the most interesting ever built it was also one of the most complex, made up of no less than three articulated sections. While powerful and extremely agile locomotives (since almost all axles were powered), the Bi-Polars’ complex design made them somewhat unreliable. After about 40 years of service the EP-2s were pulled from daily use in the late 1950s. Today, one Bi-Polar remains preserved although having been kept outdoors for decades the unit could certainly use an overhaul (notably, a new paint job).

The build date for the Bi-Polars and the Milwaukee Road's second-generation electric locomotives is not without meaning. The railroad had just completed much of its second electrified territory between Othello, Washington and Seattle, and thus needed new motive power to operate the route. Additionally, the government was slowly relinquishing its grip on USRA-control of the railroads back into private management, following the end of World War I, and the Milwaukee was quick to seize on the opportunity of upgrading its property.

The Bi-Polars were powerful and agile locomotives although they were awfully heavy and proved to be a maintenance headache due to their complex design. However, the design provided one important new design in electric locomotive technology. Today, motors are well known for their silent running, and the new bi-polar traction motors GE equipped on the EP-2s was one of the first to do so. This was due to the traction motors being "gearless", which meant that the armatures were mounted to the locomotives' axles instead of being housed in other areas of the unit, usually the nose where they created significant noise.

Altogether, the Milwaukee spent $1 million for the five Bi-Polars at $200,000 a piece, an incredible amount of money at that time (the electrification project would eventually cause the railroad to fall into bankruptcy in the late 1920s). Of note, just like the original boxcabs, the Bi-Polars also employed multiple-unit control (MU) later on in their service lives giving the engineer the ability to control each trailing unit from the lead unit. However, whereas the boxcabs regularly operated using this practice the Bi-Polars often were operated individually.

By the mid-1950s the locomotives had mostly been pulled from through, passenger service and relegated to branch or yard work. Additionally, one could fine the motors being employed in some type of maintenance duty along the main line, typically around Othello. One interesting note about the model, in relation to the differences of railroad's shop forces in Milwaukee and those regularly maintaining and operating electrics on Lines West. In the early 1950s the five Bi-Polars were shipped to Milwaukee to be overhauled, improve streamlining, and receive Union Pacific's Armour yellow passenger livery (this is also when they were equipped with MU capabilities). However, since eastern shop forces typically did not maintain electrics the overhauls were poorly executed. This likely resulted in the Bi-Polars soon-after retirement later that decade.

With the Milwaukee’s purchase of the famed "Little Joes" around the same time (1950) the end for the Bi-Polars came swiftly. In 1958 the Bi-Polars were pulled from service, brought east, and parked near Deer Lodge, Montana. In 1961 E-1 was scrapped followed by E-3, E-4, and E-5 in 1963. Luckily, E-2 survived the scrapper’s torch and today is preserved at the Museum of Transportation in St. Louis. For further history about the Milwaukee Road Bi-Polars please click here.

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The Milwaukee Road's Class EP-2, Bi-Polars

(A deep thanks to the Museum of the Rockies at Montana State University for allowing Ron Nixon's historic collection of the Milwaukee Road to be featured here. Please note that the photos featured on this page feature their corresponding image number so that you may quickly and easily find more information about it from their website. To view Ron Nixon's entire collection please click here.)

And, for more reading about the Milwaukee Road Bi-Polars and other electrics the railroad operated consider Electric Locomotives from Brian Solomon. Not only does the book give a nice overview about the Milwaukee Road's electrified operations it also covers American electric locomotive technology in general. If you're interested in perhaps purchasing either (or both) of these books please visit the links below which will take you to ordering information through Amazon.com, the trusted online shopping network.

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