The Milwaukee Road's Chicago-Twin Cities Hiawatha proved so popular that longer trains were needed, beyond the ability of the class A 4-4-2s to handle. In 1938 ALCo erected six class F7 4-6-4s to take over the service. With smaller-diameter 23½x30 cylinders and higher 84-inch drivers than the Milwaukee's earlier so-called "Baltics," the F7s compensated with a high 300-pound boiler pressure. They produced 50,300 pounds of tractive force and weighed 415,000 pounds without tender. For other specifications consult the commentary on the next page. This view of No. 104, taken in Milwaukee in October 1938, comes from the collection of Clifford "Mike" Southard courtesy of the Kishwaukee Valley Heritage Museum in Genoa, Illinois.