The classifications given by railroads to their steam locomotive fleets were as varied as the machines themselves with several different designations within a particular class! Milwaukee Road steam locomotives were likewise distinguished by wide range of classes from A to X. In any event, the information here is most certainly not a complete, all-time listing of the CMStP&P's steam fleet and also is merely meant to list the general types of steam locomotives operated by the railroad.
The Chicago, Milwaukee, St. Paul & Pacific, commonly known as simply the Milwaukee Road, is best remembered for its Hiawatha passenger trains and electrified main line known as the Pacific Extension. The fact that the great railroad is no longer with us is not as disheartening as knowing how and why its end came about. Its loyal and hardworking employees through the end were sadly cheated by upper management, which made a series of dumbfounding decisions beginning in the 1970s that ultimately ended in the railroad being sold to a rival in 1985.
Sometimes the Milwaukee's steam fleet is overlooked or forgotten due to the prestige the railroad's Lines West and electrified operations received, which continues to this day. However, the CMStP&P did have an impressive steam locomotive roster which included 4-8-4 Northerns, 2-6-6-2 heavy articulateds, and the ultra-fast and celebrated 4-4-2 Altantics and 4-6-4 Hudsons used in the railroad's Midwest Hiawatha services. Today only a few of these steam locomotives survive.
Class A
Milwaukee Road's Class A included its fleet of speedy 4-4-2 Atlantics ranging from Class A to A4-as.
Class B
Milwaukee Road's Class B included its fleet of 4-6-0 Ten-Wheelers ranging from Class B to B4.
Class C
Milwaukee Road's Class C included its fleet of 2-8-0 Consolidations ranging from Class C to C5-a.
Class F
Milwaukee Road's Class F included its fleet of 4-6-2 Pacifics ranging from Class F to F7. It should be noted that Class F6 and F7 included the Milwaukee's fleet of blazing fast 4-6-4 Hudsons which replaced the original Atlantics in Hiawatha service.
Class G
Milwaukee Road's Class G included more of its fleet of 4-6-0 Ten-Wheelers ranging from Class G3 to G8.
Class H
Milwaukee Road's Class H included its fleet of speedy 4-4-0 Americans ranging from Class H3 to H7-b.
Class I
Milwaukee Road's Class I included its fleet of 0-6-0 switchers.
Class J
Milwaukee Road's Class J included its fleet of 0-4-0 switchers.
Class K1
Milwaukee Road's Class K1 included its fleet of 2-6-2 Prairies.
Class L
Milwaukee Road's Class L included its fleet of 2-8-2 Mikados.
Class M2
Milwaukee Road's Class M2 included its only roster of 2-6-0 Moguls.
Class N
Milwaukee Road's Class N included its only roster of articulated steam locomotives, 2-6-6-2s ranging from Class N1 to N3.
Class S
Milwaukee Road's Class S included its fleet of 4-8-4 Northerns ranging from Class S1 to S3.
For more reading on the Milwaukee Road's steam locomotive fleet you might want to consider the book Milwaukee Road 1850-1960 Photo Archive by author Frank Jordan. The book is filled with historic photographs of the railroad's first 100 years of operations and has received excellent reviews by readers.
Also consider Perfecting the American Steam Locomotive by author J. Parker Lamb. As the name implies the book details the earliest history of steam engine technology, even before it was used in railroad applications. His book later explores the development of steam locomotive technology in the United States from the 19th through the 20th centuries, covering not only the most popular steam locomotive designs but also the most successful manufactures to build them. The book has received excellent reviews and is a great resource on steam locomotives and a fine reference tool; you should find it very useful. 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.