The Chicago and North Western Railway's Class E-2 was a 4-6-2 "Pacific" type locomotive built by the American Locomotive Company in Schenectady, New York in 1923.

Four of these locomotives gained the Class E-2-a designation in late 1934 when they were converted to burn oil instead of coal, upgraded with larger drivers, and had other changes made in order to run at higher speeds in preparation for pulling the Twin Cities–Chicago 400 the next year.

It was recorded running in excess of 108 miles per hour (174 km/h) on a fall evening that year as it raced the 85 miles (137 km) from Milwaukee to Chicago in 65 minutes, attaining its highest speeds between Highland Park and Evanston.

While fast for its day, it was not quite a match for the Milwaukee Road class A and later F7 engines, which ran the rival Hiawatha.

However, the railway decided instead to use diesel-electric EMD E3 locomotives for the 400, which replaced the E-2-a engines on the route in 1939.