The Baldwin S-12

The Baldwin S-12 was an upgraded version of its predecessor, the S-8 although both models were cataloged at the same time. Similar in size and mechanics, save for increased horsepower, this final switcher model manufactured during the 1950s sold relatively well for the company as numerous railroads and private industries purchased the model. While the locomotive did have some complaints regarding reliability it was revered for its ability to out-pull nearly anything in its class (a Baldwin trademark). The S-12 also saw the builder do away with the earlier complicated classification system and introducing one much simpler. Today, the S-12 remains one of Baldwin's best preserved diesels with at least fifteen still known to exist; seven at museums or tourist lines and eight more owned by short line SMS Lines.

Milwaukee Road S12 #909 is seen here in Hastings, Minnesota on June 24, 1964.

The Baldwin S-12 switcher began production in 1951 and by that time was technically a product of the Baldwin-Lima-Hamilton Corporation (BLH). BLH was formed through the merger of the Baldwin Locomotive Works and Lima-Hamilton in 1951 after the former came under the control of Westinghouse Electric Company, a long time supplier of internal components for Baldwin's diesels (the two companies had also collaborated on several electric locomotives dating back to the 19th century).  Thanks to the S-12's increased horsepower it sold much better than its less powerful counterpart. 

At 1,200 horsepower using Baldwin's latest prime mover, the 606A SC railroads found the locomotive quite versatile in several applications from yard and industrial work to revenue service on secondary and branch lines.  The locomotive came equipped with standard four axle (B-B) trucks and could produce a hefty 72,000 pounds of starting tractive effort (34,000 pounds continuous).  When production had ended in August, 1956 the model had been sold to several railroads like the Chicago & North Western, Jersey Central, Southern Pacific, New York Central, Southern, and the ever-loyal Pennsylvania. Additionally the military and industries purchased the locomotive including the Army, U.S. Steel, Armco Steel, American Smeting and Refining Company, Erie Mining, and others. In total, Baldwin sold 451 examples of the S-12.

Great Northern S12 #24 works the Minneapolis yard on June 14, 1964.

The S-12 was certainly Baldwin's most popular switcher in terms of its horsepower rating and general reliability. This is a significant reason why the model continues to find use in short line service today, notably on shortline SMS Lines which owns eight; their heritage includes Michigan Limestone #116, Tennessee Valley Authority #200, U.S. Navy #65-00372, demonstrator #1200, SP #1547, Erie Mining #7241, Monongahela Railway #425, and Great Northern #27. While four of these locomotives are operational, four are also used as a parts source.  Additionally, seven others can be found at museums; Patapsco & Back Rivers #345-#346, Erie Mining #403, NYC #9313, SP #1550, Texas & New Orleans (SP) #121, and Oliver Iron Mining #933.   Finally, for more information about the S-12s and all Baldwin switcher models please refer to the chart below.

Baldwin S-12 Production Roster

Owner Road Number(s) Quantity Date Built
Akron & Barberton Belt Railroad27-2821951-1952
American Smelting & Refining Company1954-195521952
Apache Railway60011952
Armco Steel Corporation70611955
Atlanta & West Point67811951
Baldwin (Demo)1200-1201, 463-46771953
Calumet & Hecla Railroad20311951
Central of Georgia311-31441953
Central Railroad Of New Jersey (CNJ)1053-105971951
Chicago & North Western1073-1076, 1106-1109, 1117-1121, 1126-1128151951- 1954
Columbia-Geneva Steel Division (U.S. Steel)33-3531956
Erie Railroad617-628121951-1952
Erie Mining400-40341955-1956
Fairless Works (U.S. Steel)GE-1 - GE-8, GE-17, GE-18101951-1952
Great Northern24-2851953
International-Great Northern Railroad (MP)9230-923231952
Kansas City Southern1160-116341951
Lehigh Valley230-243141950
McCloud River Railroad30-3121953
Michicgan Limestone & Chemical Company116-11721953
Milwaukee Road1905-1925211950-1954
Missouri-Kansas-Texas Railroad (Katy)1201-1215151951-1952
Missouri Pacific9200-9226271951-1952
Monongahela Railway400-426271953-1954
New Orleans Public Belt61-6221955
New York Central9308-9328211951-1952
Oliver Iron Mining Company93311951
Patapsco & Back Rivers Railroad335, 345-34741951-1953
Pennsylvania8100-8104, 8732-8796, 8976-8993881951-1954
Pennsylvania-Reading Seashore Lines (PRSL)6017-6021, 6028-6033111953- 1956
Rayonier, Inc.201-20221956
St. Louis, Brownsville & Mexico Railroad (MP)9227-922931952
Seaboard Air Line1462-1465, 1476-1481101952-1953
Sharon Steel Corporation1, 1021951
Sierra Railroad40, 4221955
Soo Line313-31421952
Southern Pacific1442-1463, 1492-1513, 1539-1550561951-1953
Southern Railway2290-2299101952
Tennessee Coal & Iron Railroad1200-120781950-1951
Tennessee Valley Authority1-3, 20041952-1954
Terminal Railroad Association Of St. Louis (TRRA)1250-125341952
Texas & New Olreans (SP)105-10731952
Union Terminal Railway Of Memphis (MP)9233-923971953
U.S. Air Force1841-184221952
U.S. Navy65-00292, 65-00293, 65-00315, 65-00365 - 650074, 65-00391141951- 1953
Wabash Railroad305-309101952-1953



Lehigh Valley S12 #232 runs light through Wilkes-Barre, Pennsylvania on June 12, 1972.

For more information on the Baldwin S-12 switcher locomotive consider Mike Schafer’s Vintage Diesel Locomotives which looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic Baldwins, or diesels in general, this book gives an excellent general history of both.  You may also want to consider the book Evolution of the American Diesel Locomotive by author J. Parker Lamb. As the title implies the book looks at the history and development of the diesel locomotives, covering 200 pages, from its earliest beginnings to the newest designs and models operated today. 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.

Share Your Thoughts

Have your say about what you just read! Leave me a comment in the box below. Please note that while I strive to present the information as accurately as possible I am aware that there may be errors. If you have potential corrections the help is greatly appreciated.


Related Reading



A History Of The Baldwin Locomotive Works


Baldwin Switchers



VO-660




DS-4-4-600




VO-1000




DS-4-4-750




DS-4-4-1000




S-8




DT-6-6-2000




RT624


Baldwin Road-Switchers



DRS-4-4-1500




DRS-6-4-1500




DRS-6-6-1500




AS16




AS416




AS616




RS12


Baldwin Cab Models



DR-4-4-1500




DR-6-4-1500




DR-6-4-2000




RF16


Other Designs



The "Centipede"




The "Sharknose"




The "Baby Face"