Alco "S3" Locomotives: Specs, Roster, Data Sheet

Last revised: December 22, 2024

The S3 was the third model of switcher in its "S" line that the company produced. It was virtually identical to the previous S1 model that was built from 1940 through 1950 and its interesting that American Locomotive even elected to change the unit's name given their striking similarities.

The S3 design was not quite as successful as the S1, selling about half as many units. However, it was purchased by several Canadian lines through Alco's Montreal Locomotive Works located in Montreal, Quebec.

The S1 was never offered in Canada while the S2 did witness several buyers, notably via Canadian National and Canadian Pacific. This continued with the S3 as both Class I's acquired even more of that particular model.

Today, the S3 is perhaps the least preserved of the switcher series but several are extant. At least three American-built examples are operational, Alexander Railroad #6 and #7 (of New York Central and Davenport, Rock Island & Western heritage) as well as Dardanelle & Russellville #18. In additional, several Canadian examples are preserved.

Photos

Classic car aficionados will surely enjoy this scene of Ford Motor Company S3 #6610 switches a carload of new Mustangs (among a wide range of other cool models!) at its River Rouge Plant in Dearborn, Michigan circa 1965. American-Rails.com collection.

Overview

The Alco S3 model rolled into production in February, 1950, which was about four months before the final S1 rolled out of the builder's Schenectady, New York plant.

The model deviated a bit from its earlier counterpart in that it was equipped with the more standard AAR trucks, while the S1 and S2 designs featured Alco's very own Blunt trucks (the manufacturer was one of the only major builders of diesel locomotives to design its own trucks).

Like the S1, the S3 was a standard four-axle design featuring traction motors from General Electric and air components (brakes and compressors) from Westinghouse. Both featured dynamic braking, weighed 105 tons, and carried a length of just over 44 feet.

However, the S3 also differed in some other ways as well. While both models offered a continuous tractive effort rating of around 46,000 pounds the S3 featured more starting effort, 59,700 pounds (compared to the S1's 57,500 pounds).

Additionally, the most noticeable difference, internally, was that the S3 included 660 horsepower whereas the S1 was slightly less powerful at just 600 horsepower.

Most likely the S3 sold fewer units than the S1 for a few reasons; first, railroads were probably looking for a more powerful switcher, which was already available in the S2; and second, aside from the S2, those that wanted the extra power had a second chance at doing so with the S4 (which replaced the S2).

Data Sheet and Specifications

Entered Production	2/1950 (Ford Motor Company #6605)
Years Produced	2/1950-11/20/1953
Model Specification	E1530A
Engine	539, 6-Cylinder In-Line
Horsepower	660
RPM	740
Carbody Styling	Alco
Length (Between Coupler Pulling Faces)	45' 5.75"
Width	10'
Height Above Rail Head	14' 6"
Weight	210,000 Lbs.
Trucks	B-B
Truck Type	GRS Rigid Bolster, Drop-Side Equalizer (AAR Type-A)
Truck Wheelbase	8'
Wheel Size	40"
Traction Motors	GE 731 (4)
Traction Generator	GT553
Gear Ratio	75:16
Tractive Effort Rating	46,000 Lbs. at 5 MPH.
Top Speed	60 MPH

During the course of production the S-3 switched from a short, to long-shank coupler so the locomotive could more easily negotiate curves while pulling a cut of cars.

The final short-shank variant appeared on La Salle Coke #4 (construction number 80986) on June 11, 1954. In Canada the first switcher to feature a long-shank coupler was Canadian Pacific #6523 (construction number 80987) completed on January 17, 1955.

Production Rosters

Alco

Total Built = 127

Owner	Road Number(s)	Serial Number(s)	Completion Date
Aluminum Company of America (Alcoa)	8	79534	2/1952
Ann Arbor	4-7	78400-78403	11/1950
Boston & Maine	1173, 1174	78318, 78319	9/1950
Boston & Maine	1175, 1176	78391, 78392	9/1950
Boston & Maine	1177 - 1179	79539-79541	2/1952 - 3/1952
Boston & Maine	1180	79767	3/1952
Boston & Maine	1181 - 1184	79770-79773	4/1952 - 5/1952
Boston & Maine	1185 - 1188	80051-80054	5/1952 - 6/1952
Brooks-Scanlon	101, 102	79538, 79774	2/1952, 5/1952
Champion Paper	2104	79535	1/1952
Chicago & North Western	1262, 1263	78529, 78530	6/1951
Chicago & North Western	1264, 1265	78781, 78782	7/1951
Chicago & North Western	1266, 1267	78783, 78784	8/1951
Davenport, Rock Island & Northwestern	1, 2	79532, 79533	12/1951, 1/1952
Davenport, Rock Island & Northwestern	3, 4	80056, 80057	8/1952
Davenport, Rock Island & Northwestern	5-7	80292-80294	9/1953, 10/1953, 11/1953
Davidson Chemical Division (W.R. Grace)	101	78786	8/1951
El Dorado & Wesson	18	80058	7/1952
Ford Motor Company	6605, 6606	77780, 77781	2/1950
Ford Motor Company	6607, 6608	77786, 77787	2/1950, 3/1950
Ford Motor Company	6609 - 6611	78396-78398	10/1950
Frederick Snare Corporation	7	79354	11/1951
General Portland Cement	1	78528	6/1951
Graysonia, Nashville & Ashdown Railroad	51	78785	8/1951
Greater Portland Public Development Corporation	661	78393	10/1950
Humble Oil	997	78399	11/1950
Louisville & Nashville	69 - 75	77479-77485	4/1953
Maine Central	961, 962	80290, 80291	3/1953
Mount Hood RR	50	78317	9/1950
New York Central	874 - 891	78141-78158	6/1950 - 8/1950
New York Central	892 - 899	78221-78228	8/1950
New York Central	900, 901	78229, 78230	9/1950
New York Central	902, 903	78315, 78316	9/1950
New York Central	904 - 906	78787-78789	9/1951
New York Central	907 - 911	78791-78795	9/1951 - 10/1951
New York Central	912 - 914	79351-79353	11/1951
New York Central	915, 916	79355, 79356	12/1951
Pennsylvania	8873, 8874	78404, 78405	11/1950
Pennsylvania	8875 - 8878	78506-78509	11/1950 - 12/1950
Pennsylvania	8879 - 8885	78511-78517	12/1950 - 3/1951
Solvay Processing Division (Allied Chemical)	2	79769	4/1952
Southern Pacific	1023 - 1032	78518-78527	3/1951 - 5/1951
Swift & Company	664	78790	9/1951
Texas & Northern	3, 4	79536, 79537	1/1952
Texas City Terminal	32	78510	11/1950
Texas Company (Texaco)	21, 22	79768, 80055	3/1952, 7/1952
Washington, Idaho & Montana	30	78395	10/1950
West Pittston & Exeter Railroad	6	78394	10/1950

Montreal Locomotive Works

Total Built = 163

Owner	Road Number(s)	Construction Number(s)	Completion Date
Bathhurst Power & Paper	3	77281	12/1953
Canadian Arsenals	1	77280	11/1952
Canadian National	8450 - 8461	77757-77768	11/1951 - 3/1952
Canadian National	8462 - 8468	77283-77289	12/1952 - 3/1953
Canadian National	8469 - 8483	79129-79143	5/1953 - 11/1953
Canadian National	8484 - 8493	76433-76442	3/1954 - 6/1954
Canadian National	8494 - 8498	80981-80985	6/1954 - 8/1954
Canadian Pacific	6500 - 6505	77635-77640	4/1951 - 5/1951
Canadian Pacific	6506 - 6512	77769-77775	3/1952 - 5/1952
Canadian Pacific	6513 - 6517	79116-79120	6/1952 - 8/1952
Canadian Pacific	6518 - 6522	79164-79168	9/1953 - 10/1953
Canadian Pacific	6523 - 6526	80987-80990	1/1955
Canadian Pacific	6527 - 6535	81072-81080	2/1955 - 3/1955
Canadian Pacific	6536	81171	3/1955
Canadian Pacific	6537 - 6547	81193-81203	7/1955 - 8/1955
Canadian Pacific	6548 - 6557	81505-81514	4/1956 - 5/1956
Canadian Pacific	6558 - 6561	81545-81548	5/1956 - 6/1956
Canadian Pacific	6562 - 6571	81663-81672	2/1957 - 3/1957
Canadian Pacific	6572 - 6588	82158-82174	3/1957- 6/1957
Canadian Pacific	6589 - 6600	82175-82186	7/1957 - 9/1957
Essex Terminal	103	77282	12/1952
LaSalle Coke	4	80986	6/1954
National Harbours Board	D2 - D4	77641-77643	5/1951
National Harbours Board	5 - 9	77752-77756	11/1951
Price Brothers	106*	77634	9/1950

* First S-3 built by the Montreal Locomotive Works. It wore "Canadian Pacific #7004" as a demonstrator.

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.

Pennsylvania Railroad S3 #8880, which the railroad classed as AS-6, was photographed here at Canton, Ohio on June 26, 1964, following her repaint in preparation for the impending Penn Central merger. Fred Byerly photo. American-Rails.com collection.

Reception

In the end the Alco S3 sold just 292 units. Interestingly, though, a wide range of railroads and industries purchased the model like the Pennsylvania, Chicago & North Western, Southern Pacific, Ann Arbor, New York Central, and others.

The Montreal Locomotive Works built S3s for Bathhurst Power & Paper, Canadian Arsenals, Canadian National, Canadian Pacific, Essex Terminal, LaSalle Coke, and National Harbours Board.

The MLW demonstrator was purchased by the Price Brothers (it was later picked up by CP). Overall, MLW constructed 163 S3's with CP and CN buying the majority of these (140).

A larger version of the photo featured above. American-Rails.com collection.

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