Milwaukee Road Bipolar

The Milwaukee Road class EP-2, nicknamed Bipolar for its distinctive bipolar traction motors, was a class of five electric locomotives built by General Electric in 1919 for the Milwaukee Road at a cost of about $200,000 each. Running on 3,000 volt DC power through 12 gearless traction motors mounted directly on the axles, each unit produced 4,440 horsepower and 116,000 pounds of starting tractive effort, weighed 530,000 pounds and was rated by the Milwaukee Road for 70 miles per hour, though General Electric claimed a 90 mile-per-hour capability. The Bipolars hauled the railroad's premier Olympian passenger train between Chicago and Seattle, and their gearless design ran nearly silent while eliminating the need for double-heading on steep mountain grades, giving the Milwaukee Road a clear cost advantage over steam on that route. One unit, E2, survives on static display, restored to its 1953 rebuilt condition, at the National Museum of Transportation in St. Louis.