The ALCO S-1 and S-3 are diesel-electric switcher locomotives produced by ALCO and their Canadian subsidiary Montreal Locomotive Works (MLW). The two locomotives differed only in trucks, with the S-1 using ALCO's own Blunt trucks, and the S-3 using AAR type A switcher trucks. The S-1 was built between April 1940 and June 1950, with a total of 543 completed, while the S-3 was constructed between February 1950 and November 1953 (MLW until 1957) with total sales of 300. A modified version, the S-10, was built by MLW only; 13 were built between January and June 1958.

Identification The S-1 and S-3 are distinguishable externally from the very similar S-2 and S-4 switchers in that they have a smaller exhaust stack with a round base and a smaller radiator shutter area on the nose sides. The S-1/S-3 radiator shutter area is taller than it is wide, while the S-2/S-4 radiator area is wider. The smaller stack is due to the lack of turbocharging.

The S-10 is not externally distinguishable from later Canadian-built S-3 locomotives; it differed mostly in electrical equipment.

Original owners The S-1 and S-3 models were sold to an extensive list of railroads and industrial operators, as detailed below. Major owners of the S-1 included the New York Central Railroad (NYC), with 71 locomotives; the New Haven with 65 locomotives; the L&N with 45 locomotives; the C&NW, with 29 locomotives; and the Pennsylvania Railroad (PRR) with 27 locomotives. Major customers for the S-3 included the CP, with 101; the CN, with 49; the NYC, with 43 locomotives; the B&M, with 16; and the PRR, with 13. The MLW S-10 was sold only to the CP.

The totals below include export orders and MLW-built locomotives.

S-1 ALCO constructed approximately 535 S-1s for the US market between 1940 and 1950. Railroad Quantity Road numbers Alabama Great Southern Railroad 2 6501–6502 Alameda Belt Line 3 D-1–D-3 Alco (demonstrator) 1 660 Alco (plant switcher) 1 5 Alco/War Department 1 GT-1304 American Steel & Wire 1 2 Ann Arbor Railroad 2 2–3 ARMCO Steel 3 E106–E108 Atchison, Topeka and Santa Fe Railway 2 2303–2304 Baltimore and Ohio Railroad 6 223–227, 250 Belt Railway of Chicago 3 304–306 Birmingham Southern Railroad 2 100, 101 Boston and Maine Railroad 10 1163–1172 Broward County Port Authority 1 410 Canadian Car and Munitions 1 5 Estrada de Ferro Central do Brasil 5 3001–3005 Central of Georgia Railway 2 4, 6 Central Railroad of New Jersey 2 1024, 1025 Champlain Paper and Fibre 1 25 Chicago and Eastern Illinois Railroad 3 103–105 Chicago and North Western Railway 29 1202–1205, 1213, 1223–1229, 1232–1236, 1247–1258 Chicago Great Western Railway 5 11–15 Chicago, St. Paul, Minneapolis and Omaha Railway 3 56, 57, 69 Cincinnati, New Orleans and Texas Pacific Railway 2 6000–6001 City of Prineville Railway 1 101 Donner Hanna Coal Company 1 2 Day and Zimmerman (Iowa Army Ammunition Depot) 1 3-100 Defense Plant Corporation 2 DPC25.23, DPC25.24 Delray Connecting Railroad 4 66, 68, 70, 72 Des Moines Union Railway 4 1–4 Detroit and Mackinac Railway 1 646 East St. Louis Junction Railroad 1 100 Elgin, Joliet and Eastern Railway 5 213–217 Erie Railroad 16 306–321 Ford Motor Company 4 6601–6604 Great Lakes Steel Corporation 1 32 Green Bay and Western Railroad 1 102 Gulf, Mobile and Ohio Railroad 4 661–664 Hunken Conkey Construction 2 1001–1002 Inland Steel 7 53, 56, 61, 62, 64–66 Inland Waterways Corporation 1 1 Iowa Transfer Railroad 1 2 John Morrell & Co. 1 7 Kansas City Terminal Railway 5 40–44 Kewaunee, Green Bay and Western Railroad 1 103 Lehigh Valley Railroad 1 117 Long Island Rail Road 14 404–408, 413–420, 421 Louisville and Nashville Railroad 45 16–29, 34–68 Maine Central Railroad 8 953–960 Massena Terminal Railroad 2 8, 9 Minnesota Transfer Railway 5 60–64 Missouri Pacific Railroad 2 9007, 9008 Nashville, Chattanooga and St. Louis Railway 4 1–4 Ferrocarriles Nacionales de México 5 5000-5004 Newburgh and South Shore Railway 7 3–7, 9, 10 New Orleans and Lower Coast Railroad 3 9013-9015 New York, New Haven and Hartford Railroad 65 0931–0995 New Jersey, Indiana and Illinois Railroad 1 1 New York Central Railroad 71 590, 685–744, 864–873 New York, Chicago and St. Louis Railroad 1 85 Northern Pacific Railway 1 131 Northern Pacific Terminal 5 30–34 Pennsylvania Railroad 27 5661–5670, 5954–5956, 9100–9103, 9237–9246 Point Comfort and Northern Railway 1 5 Port Huron and Detroit Railroad 2 51, 52 Portland Terminal Company 4 1005-1008 Procter & Gamble 1 9 Pullman Railroad 2 20, 21 Reading Company 5 50-54 Red River Ordnance Depot 1 7372 Republic Steel 9 15–17, 312–314, D840, D841, D810 River Terminal Railway 1 52 St. Louis and O'Fallon Railway 1 51 Seaboard Air Line 1 1201 Sheffield Steel Corporation 3 11–13 Solvay Processing Division, Allied Chemical 3 1–3 South Buffalo Railway 4 51, 52, 60, 61 Southern Pacific Company 4 1017–1020 Southern Railway 3 2000, 2001, 2006 South Omaha Terminal Railway 5 1–5 Spokane, Portland and Seattle Railway 2 10, 11, 10 Sold to City of Prineville 102, 11 to Burlington Northern 11 Steel Company of Wales (UK) 5 801–805 Studebaker 2 2, 3 Tennessee Central Railway 1 51 Tennessee Coal, Iron and Railroad Company 3 700–702 Tennessee Copper 2 104, 105 Terminal Railroad Association of St. Louis 4 521–524 Texas and New Orleans Railroad 1 10 Texaco 1 19 Texas City Terminal Railway 2 30, 31 Texas Pacific-Missouri Pacific Terminal Railroad of New Orleans 2 3, 4 Timken Rolling Bearing Company 2 5911, 5912 Toledo, Angola and Western Railway 1 101 Traux Truer Coal 1 10 Union Railroad 4 451–454 Upper Merion and Plymouth Railroad 1 54 U.S. Army 11 7132-7136, 7141-7142, 7374-7375, 7459-7460 Wabash Railroad 9 151–159 Weirton Steel 3 200, 203, 204 Western Maryland Railway 1 102 Western Pacific Railroad 8 504–511 Youngstown Sheet and Tube 5 661–665 Total 543

S-3 ALCO and the Montreal Locomotive Works constructed approximately 300 S-3s for the North American market between 1950 and 1957. Railroad Quantity Road numbers Manufactured by ALCOAluminum Company of America 1 8Ann Arbor Railroad 4 4–7Boston and Maine Railroad 16 1173–1188Brooks and Scanlon 2 101, 102Champion Paper 1 2104Chicago and North Western Railway 6 1262–1267Davenport, Rock Island and North Western Railway 7 1–7Davidson Chemical Division, W.R. Grace and Company 1 101El Dorado and Wesson Railway 1 18Ford Motor Company 7 6605–6611Frederick Snare Corporation 1 7General Portland Cement 1 1Graysonia, Nashville and Ashdown Railroad 1 51Greater Portland Public Development Corporation 1 661Humble Oil 1 997Louisville and Nashville Railroad 7 69–75Maine Central Railroad 2 961, 962Manistique and Lake Superior Railroad 1 1Mount Hood Railroad 1 50New York Central Railroad 43 874–916Pennsylvania Railroad 13 8873–8885Solvay Processing Division, Allied Chemical and Dye Corporation 1 2Southern Pacific Company 10 1023–1032Swift and Company 1 664Texas and Northern Railway 2 3, 4Texas City Terminal Railway 1 32Texaco 2 21, 22Washington, Idaho and Montana Railway 1 30West Pittston and Exeter Railway 1 6 ALCO total 137 Manufactured by MLWBathhurst Power and Paper 1 3 Canadian Arsenals 1 1 Canadian National Railway 49 8450–8498Canadian Pacific Railway 101 6500–6600Essex Terminal Railway 1 103LaSalle Coke 1 4National Harbours Board 8 D2–D9 Price Brothers 1 106MLW subtotal 163 Total 300

S-10 MLW constructed 13 S-10s in 1958, all for the Canadian Pacific Railway, numbered 6601–6613. These units were essentially similar to late-built S3s, though with minor updates to the electrical gear.

S-11 In 1959, MLW built a final order of 660 horsepower switchers for the Canadian Pacific, as model S-11, numbered 6614–6623. The internal machinery of these units was essentially the same as that of the S-10, but the car body was radically redesigned, with the radiator on the front end of the hood instead of on the sides.Kirkland, John, "The Diesel Builders, volume 2: Also" Interurban Press, 1989

Preservation

Numerous S-1 and S-3 locomotives remain in use, and several are preserved: Ex-U.S. Army S-1 7372 is at the Western Pacific Railroad Museum and painted in Western Pacific colors. Ex-Canadian Pacific MLW S-3 6568 is at the Saskatchewan Railway Museum. One Ex-Steel Company of Wales S-1 No. 801 is preserved and is being restored to working order at the Nene Valley Railway in England. Ex-Erie Railroad S-1 No. 307 is preserved at Riverside Park, Manhattan and painted in New York Central colors. Ex-Erie Railroad S-1 No. 308 is preserved at the New York and Lake Erie Railroad Ex-Tennessee Central No. 51, later Cadiz Railroad No. 8, was on display in Trigg County, KY near exit 65 of Interstate 24. The unit is now currently in private ownership in nearby Christian County. Ex-New York Central No. 872, later Bath and Hammondsport No. 5, was acquired by the Rochester & Genesee Valley Railroad Museum in March 2025. Ex-South Omaha Terminal No. 1, later Hutchinson Northern Railroad No. 4, is owned by the Abilene and Smokey Valley Railroad. Number 4 was donated in 1993 and still runs excursions.

See also List of ALCO diesel locomotives List of MLW diesel locomotives

References

External links

Alco/MLW S-1 Roster Alco/MLW S-3 Roster