Alco "S-4" Locomotives


The Alco S4 was the fourth model of switcher series the company produced and debuted a decade after the S1 and S2 designs in 1949. The American Locomotive Company (Alco) began production on the S4 directly after the S2 in June, 1950. It was quite apparent that railroads preferred Alco's more powerful small switchers as both the S2 and S4 far outsold both the S1 and S3 by more than 1,400 units! While not quite as popular as the S2, the S4 still sold nearly 800 examples and could likewise by found on railroads and within industrial settings all around the country. Alco's Montreal Locomotive Works branch (located in Montreal, Quebec) also saw a large number of orders from Canadian lines. Today, the S4 is one of the best preserved examples of Alco diesel locomotives as more than a dozen are either preserved or in operation on numerous museums and tourist lines around the country.

Portland Terminal S4 #1061 (built as Delaware & Hudson #3041 in 1950 and acquired in 1967) works the Portland, Maine waterfront on August 4, 1968. Roger Puta photo.








The Alco S4 design began production in June, 1950 as soon as the last S2 had rolled off of the assembling line. The model is only slightly different from its earlier S2 sibling with minor carbody variations such as a relocation of the bell from behind the exhaust stack to the front of the hood (unless otherwise requested). Otherwise, externally both models could hardly be distinguished from the other. Internally, both designs featured four axles and traction motors and air components from General Electric and Westinghouse. They also both used McIntosh & Seymour's model 539 prime mover that could produce 1,000 horsepower and featured turbocharging.  Finally, each model weighed in at just under 115 tons.

Morristown & Erie S4 #14 is seen here at Whippany, New Jersey on April 26, 1969. Roger Puta photo.

There were more striking differences, though. The S4 came equipped with updated type A AAR trucks whereas the S2 had used Alco's very own Blunt trucks (one of the only manufacturers to design its own trucks). Additionally, the S4 offered much more tractive effort (a big advantage in the world of switching and shuffling cars); 72,400 pounds starting and 34,000 pounds continuous compared to the S2's 69,000 pounds starting and 29,200 continuous. Interestingly, while few Canadian or foreign  lines purchased early models of Alco's Switcher class (the S1 and S2) many bough examples of later designs like the S3 and S4. The S4 also attracted many more industries due to the fact that it featured increased horsepower and tractive effort but retained the same size and dimensions of earlier models (making it agile and maneuverable in the tight spaces of such settings).

During a beautiful late summer evening, Southern Pacific S4 #1825 appears to be switching the 3rd & Townsend Depot in San Francisco as an H24-66 "Train Master" can be seen in the background on August 25, 1967. Roger Puta photo.

Following the Alco S4 the company had a difficult time selling switchers, which was partly due to the fact that railroads began to find that road switchers could perform the tasks of switching and shuffling cars just as well, and could also be used in regular freight service. While the specialized needs of a switcher diminished to some extent by the 1960s, when Alco completed production of the S4 in 1961 it had sold some 782 units in total. The Canadian lines including the Canadian Pacific, Canadian National, Ontario Northland, Asbestos & Danville, Alma & Janquiere and industries Abitibi Power & Paper, Falconbridge Nickel Mines, and Quebec Iron & Titanium picked up some 145 S4s through Alco's Montreal Locomotive Works. The CN would come to own the most of these buying 113 units.  Interestingly, after the S4 Alco would sell less than 200 examples of its final three switcher designs including the special order S5, S6, and transfer model T6.  For more information about the S4 please click here.  

Alco S4 Production Roster (U.S. Only)

Owner Road Number(s) Quantity Date Built
Algiers, Winslow & Western Railway1-221953
Angelina & Neches River1211958
Armco Steel CorporationE111-E114, E11651954-1960
Baltimore & Ohio468-474, 534-545, 9078-9114561953-1957
Bessemer & Lake Erie291-29221952
Central Vermont Railway8015, 8027, 8080-808141951-1955
Chesapeake & Ohio5100-5113141953
Chicago & North Western1077-1079, 1093-1099101951-1955
Chicago, St. Paul, Minneapolis & Omaha (C&NW)10111952
Cincinati, New Orleans & Texas Pacific (Southern)6074-607521951
Delaware & Hudson3033-3050281950
Erie Railroad526-52941951-1952
Fairport, Painesville & Eastern10511951
Ford Motor Company10008-1001251954
Genesee & Wyoming3511959
Georgia Port Authority10111952
Grafton & Upton100111952
Grand Trunk Western8026, 8034-8035, 8082-8090, 8196-8205221953-1956
Hammond Lumber Company10111950
Houston Belt & Terminal20-2121951
Ideal Cement Company5511955
Illinois Northern29-3461950-1951
Kaiser Steel Corporation1011-1013, 1015-101981951-1957
Lehigh Valley166-16721951
Longview, Portland & Northern11211951
Los Angeles Junction Railway6-721950-1953
Louisville & Nashville2225-2232, 2350-2369281951-1953
Maine Central311-31771950-1954
Manufacturers Railway (St. Louis)21211951
Massena Terminal1111951
Michigan Limestone & Chemical Company11511950
Milwaukee Road1863-1896341950-1954
Minnesota Transfer100-10561951/td>
Monongahela Connecting139-14351951
Morristown & Erie1411952
National Lead Company911954
New Jersey Zinc Company2311953
New York Central8590-8532411952
Nickel Plate Road46-61, 65-83351951-1953
Northeast Oklahoma Railroad705-70621950-1952
Northern Pacific713-724121951-1953
Northern Pacific Terminal42-4541952-1954
Pennsylvania8430-8434, 8487-8499, 8886-8901341950-1954
Piedmont & Northern1000-100561954
Pittsburgh & Lake Erie (NYC)8633-8667351950-1953
Portland Terminal (Maine)1055-105841950
Santa Fe1500-1537381952-1953
Schafer Brothers Logging Company2011950
Seaboard Air Line1482-1491101953
South Buffalo Railway92-9981951-1952
Southern Pacific1464-1485, 1514-1528, 1551-1567441951-1955
Tennessee Copper Company10611953
Terminal Railway Alabama State Docks511, 521, 541, 57141951-1957
Texas & New Orleans (SP)95-104101951
Texas & Northern10-1121951
Texas City Terminal3311953
Toledo Terminal109-11131951-1952
Union Pacific1154-1198451955-1956
Union Railroad536-53721951
U.S. Steel111955
Wabash Railroad322-32431953
Weirton Steel210-21451951-1959
Western Maryland145-14621951
Western Pacific563-56421951
Wisconsin Central (Soo)211611952
Youngstown & Northern222-22321950-1951


Grand Trunk Western S4 #8203 is seen here at Elsdon Yard in Chicago during July, 1964. Roger Puta photo.

For a comprehensive look at the American Locomotive Company and all of the motive power types it built from steam, diesel, to electrics consider the book Alco Locomotives by Brian Solomon. Covering more than 175 pages Mr. Solomon's book details the history of Alco from its esteemed 4-6-4 Hudsons and 4-6-6-4 Challengers to vaunted RS and PA series diesel locomotives. If you have any interest in Alco this book is a must have!  Also 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.   To read more about other Alco switchers please visit the Diesel Locomotives section of the site, which can be reached from the top of this page.




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Header Photo: Drew Jacksich



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