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Alco "S-4" Locomotives

Last revised: June 22, 2023

By: Adam Burns

The 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.

Photos

ou423758723589262896839478938.jpgChessie System/B&O S4 #9007 at the Glenwood Roundhouse in Hazelwood, Pennsylvania (Pittsburgh), circa 1974. Warren Calloway collection.

Overview

The Alco S4 design began production in June, 1950 (Schenectady) 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).

2860203952734623742756789420893509789.jpgSt. Louis-San Francisco Railway (Frisco) S4 #298 carries out switching chores in Miami, Oklahoma, circa 1970. This unit was built as Northeast Oklahoma Railroad #706. Mac Owen photo. American-Rails.com collection.

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.

20350923572374275786893893907489.jpgPennsylvania S4 #8434 was photographed here in Detroit, Michigan between assignments, circa 1964. Fred Byerly photo. American-Rails.com collection.

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).

Morristown & Erie S4 #14, the road's only example, carries out switching work at Roseland, New Jersey, circa 1960. Meyer Pearlman photo. American-Rails.com collection.

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 1960 it had sold some 782 units in total.

92347235872389523785723689378.jpgErie Lackawanna S4 #529, still in its former Erie paint, was photographed here at Meadville, Pennsylvania on March 26, 1972. Photographer unknown. American-Rails.com collection.

Data Sheet and Specifications

Entered Production (Alco)8/3/1950 (Maine Central #311-312)
Entered Production (MLW)6/1949 (Canadian Pacific #7099)
Years Produced (Alco)8/3/1950-1960 (Armco Steel Corporation E116)
Years Produced (MLW)6/1949-1/1957 (Canadian National #8195)
Model SpecificationE1540A/B
Engine539T, 6-Cylinder In-Line
Horsepower1000
RPM740
Carbody StylingAlco
Length (Between Coupler Pulling Faces)45' 5.75"
Width10'
Height Above Rail Head14' 6"
Weight230,000 Lbs.
TrucksB-B
Truck TypeGRS Rigid Bolster, Drop-Side Equalizer (AAR Type-A)
Truck Wheelbase8'
Wheel Size40"
Traction MotorsGE 731 (4)
Traction GeneratorGT563
Gear Ratio75:16
Tractive Effort Rating34,000 Lbs. at 8 MPH.
Top Speed60 MPH

The primary difference between E1540A and E1540B was the switch from short to long-shank couplers.  The transition occurred in Schenectady in 1954:

  • Piedmont & Northern #1005 (construction number 81094) was the final to receive short-shank couplers and completed on April 27, 1954.

  • Armco Steel #E111 (construction number 81095) was the first to receive long-shank couplers, completed on April 30, 1954.

At the Montreal Locomotive Works the change took place between 1954 and 1955:

  • Canadian National #8033 (construction number 76448) was the final to receive short-shank couplers, completed on March 10, 1954.

  • Falconbridge Nickel Mines #108 (construction number 76449) was the first to receive long-shank couplers, completed on July 15, 1955.
384602395273572698378483900983.jpgMilwaukee Road S4 #818 (built as #1895) was photographed here at Kansas City, Missouri in December of 1968. Fred Byerly photo. American-Rails.com collection.

Production Roster

Alco

Total Built = 651

Owner Road Number(s) Serial Number(s) Completion Date
Algiers, Winslow & Western 1, 2 79818, 79819 4/1953
Altos Hornos de Mexico, S.A.B. de C.V. (AHMSA) 111 1 78717 4/1951
Altos Hornos de Mexico, S.A.B. de C.V. (AHMSA) 115 1 81333 5/1955
Altos Hornos de Mexico, S.A.B. de C.V. (AHMSA) 117, 118 2 82004, 82005 8/1957
Altos Hornos de Mexico, S.A.B. de C.V. (AHMSA) 121 1 82010 3/1961
Angelina & Neches River 12 82006 9/1958
Armco Steel E111, E112 81095, 81100 12/1954
Armco Steel E113, E114 81334, 81335 5/1955
Armco Steel E116 82009 5/1960
Santa Fe 1500 - 1509 78767-78776 5/1951-6/1951
Santa Fe 1510 - 1519 78805-78814 7/1951
Santa Fe 1520 - 1525 79809-79814 7/1952
Santa Fe 1526 - 1529 80059-80062 7/1952-8/1952
Santa Fe 1530 - 1537 80613-80620 6/1953
Baltimore & Ohio 468 - 474 81320-81326 4/1955
Baltimore & Ohio 534 - 539 80954-80959 11/1953-12/1953
Baltimore & Ohio 540, 541 80962, 80963 12/1953
Baltimore & Ohio 542 - 545 81327-81330 4/1955
Baltimore & Ohio 9078 - 9097 81860-81879 4/1956-6/1956
Baltimore & Ohio 9098, 9099 81971, 81972 6/1956
Baltimore & Ohio 9100 - 9114 81985-81999 2/1957-8/1957
Bessemer & Lake Erie 291, 292 80054, 80065 7/1952
Boston & Maine 1266 - 1273 78021-78028 8/1950
Central Vermont 8015, 8027 79227, 80467 10/1951, 5/1953
Central Vermont 8080, 8081 81400, 81401 9/1955
Chesapeake & Ohio 5100 - 5104 80622-80626 7/1953-8/1953
Chesapeake & Ohio 5105 - 5113 80629-80637 8/1953-9/1953
Chicago & North Western 1077 - 1079 81397-81399 8/1955
Chicago & North Western 1093 - 1099 78828-78834 8/1951
Milwaukee Road 1863 - 1867 78421-78425 11/1950
Milwaukee Road 1868 - 1872 78718-78722 4/1951
Milwaukee Road 1873 - 1884 78844-78855 10/1951
Milwaukee Road 1885 - 1887 79216-79218 10/1951
Milwaukee Road 1888 - 1891 80083-80086 10/1952
Milwaukee Road 1892 - 1896 80969-80973 12/1953-1/1954
Chicago, St. Paul, Minneapolis & Omaha (C&NW) 101 80621 7/1952
Cincinnati, New Orleans & Texas Pacific (Southern) 6074, 6075 78337, 78338 9/1951
Delaware & Hudson 3033 - 3036 78029-78032 9/1950
Delaware & Hudson 3037 - 3046 78231-78240 9/1950
Delaware & Hudson 3047 - 3050 78406-78409 10/1950
Erie Railroad 526, 527 78716, 79530 4/1951, 1/1952
Erie Railroad 528, 529 80089, 80090 10/1952
Fairport, Painesville & Eastern 105 79225 10/1951
Ferrocarriles Nacionales de México 5523 - 5530 8 78816-78823 7-8/1951
Ford Motor Company 10008 - 10011 81102-81105 12/1954
Ford Motor Company 10012 81126 12/1954
Genesee & Wyoming 35 82008 6/1959
Georgia Port Authority 101 80091 10/1952
Grafton & Upton 1001 79805 6/1952
Grand Trunk Western 8026 80466 5/1953
Grand Trunk Western 8034, 8035 81331, 81332 5/1955
Grand Trunk Western 8082 - 8084 81402-81404 9/1955
Grand Trunk Western 8085 - 8090 81436-81441 10/1955
Grand Trunk Western 8196 - 8205 81973-81982 7/1956-9/1956
Hammond Lumber Company 101 78140 6/1950
Houston Belt & Terminal 20, 21 78723, 78724 4/1951
Ideal Cement Company 55 81442 10/1955
Illinois Northern 29 - 31 78413-78415 10/1950
Illinois Northern 32, 33 79228, 79229 10/1951
Illinois Northern 34 79500 12/1951
Kaiser Steel 1011 78815 8/1951
Kaiser Steel 1012, 1013 79806, 79807 6/1952
Kaiser Steel 1015, 1016 81983, 81984 10/1956-11/1956
Kaiser Steel 1017 - 1019 82001-82003 8/1957
Lehigh Valley 166, 167 78725, 78766 5/1951
Longview, Portland & Northern 112 79226 10/1951
Los Angeles Junction 6, 7 78410, 80628 10/1950, 8/1953
Louisville & Nashville 2225 - 2232 79492-79499 11/1951-12/1951
Louisville & Nashville 2350 - 2365 80067-80082 8/1952-9/1952
Louisville & Nashville 2366 - 2369 80453-80456 5/1953-6/1953
Maine Central 311, 312 78008, 78020 8/1950
Maine Central 313 79502 12/1951
Maine Central 314 - 317 81096-81099 9/1954
Manufacturers Railroad 212 78835 8/1951
Massena Terminal 11 79219 10/1951
Michigan Limestone & Chemical 115 78420 11/1950
Minnesota Transfer 100 - 105 78796-78801 6/1951
Monongahela Connecting Railroad 139 - 143 78339-78343 9/1951
Morristown & Erie 14 79786 4/1952
National Lead Company 9 81101 10/1954
New Jersey Zinc Company 23 80638 9/1953
New York Central 8590 79531 2/1952
New York Central 8591 - 8607 79542-79558 2/1952
New York Central 8608 - 8618 79561-79571 3/1952
New York Central 8619 - 8629 79775-79785 3/1952-4/1952
New York Central 8630 - 8632 79788-79790 5/1952
New York, Chicago & St. Louis (Nickel Plate Road) 46 - 52 78697-78703 1/1951
New York, Chicago & St. Louis (Nickel Plate Road) 53 - 60 78704-78711 3/1951
New York, Chicago & St. Louis (Nickel Plate Road) 61 79520 1/1952
New York, Chicago & St. Louis (Nickel Plate Road) 65 - 73 79521-79529 1/1952
New York, Chicago & St. Louis (Nickel Plate Road) 74 - 77 80468-80471 5/1953
New York, Chicago & St. Louis (Nickel Plate Road) 78 - 83 80447-80452 5/1953
Northeast Oklahoma 705, 706 77041, 80066 2/1950, 8/1952
Northern Pacific 713 79230 10/1951
Northern Pacific 714 - 716 79331-79333 10/1951-11/1951
Northern Pacific 717 - 719 80462-80464 5/1953
Northern Pacific 720 - 724 80964-80968 12/1953
Northern Pacific Terminal 42, 43 79559, 79560 3/1952
Northern Pacific Terminal 44, 45 80297, 80298 1/1954
Pennsylvania 8430 - 8432 80975-80977 1/1954
Pennsylvania 8433, 8434 80295, 80296 1/1954, 2/1954
Pennsylvania 8487 - 8499 79792-79804 5/1952-6/1952
Pennsylvania 8886 - 8899 78683-78696 11/1950-12/1950
Pennsylvania 8900, 8901 78779, 78780 6/1951
Piedmont & Northern 1000 - 1005 81089-81094 10/1954
Pittsburgh & Lake Erie (NYC) 8633 - 8638 80639-80644 9/1953
Pittsburgh & Lake Erie (NYC) 8639 - 8643 80645-80649 10/1953
Pittsburgh & Lake Erie (NYC) 8644 - 8653 80930-80939 10/1953
Pittsburgh & Lake Erie (NYC) 8654 - 8667 80940-80953 11/1953
Portland Terminal (Maine) 1055 - 1058 78416-78419 11/1950
Schafer Brothers Logging Company 20 78412 10/1950
Seaboard Air Line 1482 - 1486 79820-79824 4/1953
Seaboard Air Line 1487 - 1491 80457-80461 4/1953-5/1953
Secretaría de Marina Nacional 101, 102 2 81127, 81128 1/1955
South Buffalo Railway 92 - 95 78824-78827 8/1951
South Buffalo Railway 96, 97 79518, 79519 1/1952
South Buffalo Railway 98, 99 79787, 80063 5/1952, 7/1952
Southern Pacific 1464 - 1470 79339-79345 11/1951
Southern Pacific 1471 - 1485 79503-79517 12/1951
Southern Pacific 1514 - 1525 80092-80103 3/1953
Southern Pacific 1526 - 1528 79815-79817 4/1953
Southern Pacific 1551 - 1557 81129-81135 3/1955
Southern Pacific 1558 - 1567 81310-81319 3/1955-4/1955
Tennessee Copper 106 80465 5/1953
Terminal Railway-Alabama State Docks 511, 521 78804, 80088 8/1951, 10/1952
Terminal Railway-Alabama State Docks 541, 571 80974, 82000 1/1954, 8/1957
Texas & New Orleans (SP) 95 - 99 79220-79224 10/1951-11/1951
Texas & New Orleans (SP) 100 - 104 79334-79338 11/1951
Texas & Northern 10, 11 78802, 78803 6/1951
Texas City Terminal 33 80627 8/1953
Toledo Terminal 109, 110 78712, 78713 4/1951
Toledo Terminal 111 80087 9/1952
Union Pacific 1154 - 1162 81336-81344 6/1955
Union Pacific 1163 - 1173 81385-81395 6/1955-7/1955
Union Pacific 1174 - 1186 81443-81455 11-12/1955
Union Pacific 1187 - 1198 81825-81836 12/1955-3/1956
Union Railroad 536, 537 78714, 78715 4/1951
U.S. Steel 1 81396 6/1955
Wabash 322 - 324 80610-80612 6/1953
Weirton Steel 210, 211 78836, 79808 9/1951, 6/1952
Weirton Steel 212, 213 81837-81839 11/1956
Weirton Steel 214 82007 6/1959
Western Maryland 145, 146 78681, 78682 1/1951
Western Pacific 563, 564 78777, 78778 5/1951
Wisconsin Central (Soo Line) 2116 79791 5/1952
Youngstown & Northern 222, 223 78411, 79501 10/1950, 12/1951

Montreal Locomotive Works

Total Built = 146

Owner Road Number(s) Serial Number(s) Completion Date
Abitibi Power & Paper Company 80 77585 6/1950
Alma & Janquiere Railway 101, 102 76469, 77589 8/1949, 7/1951
Asbestos & Danville 46, 47 76495, 77587 11/1949, 9/1950
Asbestos & Danville 48, 49 77294, 81258 8/1953, 8/1956
Canadian National 7995 - 7999 76481-76485 8/1949-9/1949
Canadian National 8000 - 8005 (originally numbered 7600 - 7605) 76486-76491 9/1949-10/1949
Canadian National 8006, 8007 (originally numbered 7606 - 7607) 76493, 76494 10/1949
Canadian National 8008 - 8011 (originally numbered 7608 - 7611) 76496-76499 10/1949-11/1949
Canadian National 8012 - 8015 77581-77584 12/1949-1/1950
Canadian National 8016, 8017 77596, 77597 12/1951
Canadian National 8018 - 8025 77598-77605 9/1952-11/1952
Canadian National 8028 - 8033 76443-76448 1/1954-3/1954
Canadian National 8036 - 8038 79193-79195 8/1955-9/1955
Canadian National 8039 - 8050 81217-81228 9/1955-11/1955
Canadian National 8051 - 8077 81231-81257 12/1955-2/1956
Canadian National 8078, 8079 81229, 81230 11/1955
Canadian National 8163 - 8170 81259-81266 8/1956-9/1956
Canadian National 8171 - 8180 81549-81558 9/1956-10/1956
Canadian National 8181 - 8190 81573-81582 10/1956-12/1956
Canadian National 8191 - 8195 81653-81657 12/1956-2/1957
Canadian Pacific 7099 - 7105 76469-76475 6/1949
Canadian Pacific 7106 - 7108 76476-76478 7/1949
Canadian Pacific 7109 - 7114 77590-77595 7/1952-8/1952
Canadian Pacific 7115 - 7118 77290-77293 3/1953-5/1953
Falconbridge Nickel Mines 108 76449 1/1955
Ontario Northland 1203 77586 12/1950
Quebec Iron & Titanium (Romaine River Railway) 1, 2 76480, 76492 8/1949, 10/1949
Quebec Iron & Titanium (Romaine River Railway) 4 77588 5/1951

* First MLW-built S4 with long-shank couplers.

Sources

  • Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.
  • Kirkland, John F. Diesel Builders, The:  Volume Two, American Locomotive Company And Montreal Locomotive Works. Glendale: Interurban Press, 1989.
  • Pinkepank, Jerry A. Diesel Spotter's Guide.  Milwaukee: Kalmbach Publishing Company, 1967.
  • Solomon, Brian. Alco Locomotives. Minneapolis: Voyageur Press, 2009.

Penn Central S4 #9832 (built as Pennsylvania #8432). Location not recorded. September, 1969. American-Rails.com collection.

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.  

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