EMD "SW7" Locomotives: Data, Specs, Roster

Last revised: December 20, 2024

The SW7 was Electro-Motive third in its modern switcher line and the first produced after World War II.

EMD had halted production on new models until after the war due to restrictions brought about the War Production Board, which directed companies to focus on materiel for the war effort.

Outwardly, the SW7 was virtually identical to the NW2 and later "SW" models through the SW1200. Once again, there were a wide range of buyers for this locomotive from large Class I's to short lines and private industries.

Both builders and railroads alike came to realize the 1,000-1,500 horsepower switcher was the ideal rating; it offered plenty of beef, yet remained small enough to handle the assignments required of these locomotives (such as tight clearances and sharp curves).

As with many early EMD switcher models, the SW7 continues to see use today. It remains in operation at some private industries and also on short lines.

Photos

Chesapeake & Ohio SW7 #5224 pushes cars into the "S.S. Badger" carferry at Ludington, Michigan in July, 1960. Rick Burn photo.

History and Background

The SW7 debuted in October, 1949 as Electro-Motived looked to continue the strong sales of its earlier SW1 and NW2 models.

These two switchers had been a massive success, combining for 1,775 units during a production run that spanned fifteen years (1938-1953). The NW2, alone, had sold 1,115 units.

The history of the SW line dates back to the Electro-Motive Corporation a series of cast and welded-framed models built between 1935-1939.

This switchers sported 600 horsepower and, coupled with their 900 horsepower counterparts (NW/NC), convinced the builder there was a market for such a locomotive.

The SW7 used the traditional EMC/EMD carbody design, that was tapered near the cab and featured EMD's classic conical exhaust stacks. Length remained the same at just over 44-feet and the model continued to use GM's D37 traction motors.

Kansas City Southern SW7 #1312 is seen here in Kansas City, Missouri, circa 1973. Mac Owen photo. American-Rails.com collection.

12-Cylinder, 567A

The biggest difference was a bump in horsepower; sporting an updated, 12-cylinder model 567A prime mover, the SW7 could produce a hefty 1,200 horsepower with a starting tractive effort of 62,000 pounds.

By the time the switcher was cataloged, the "SW" designation had changed: "S" no longer stood for six-hundred horsepower and "W" did not mean welded frame.

Data Sheet and Specifications

Entered Production	10/1949 (Indiana Harbor Belt #8835)
Years Produced	10/1949 - 1/1951
EMD Class	SW7
Engine	567A (12 Cylinder)
Engine Builder	EMD/GM
Horsepower	1200
RPM	800
Length	44' 5"
Height (Top Of Rail To Top Of Cab)	14' 6"
Width	10' 2"
Weight	248,000 Lbs
Fuel Capacity	600 Gallons
Air Compressor	WXO (Gardner-Denver)
Air Brake Schedule	14EL (Westinghouse)
Trucks	B-B
Truck Type	GRS Rigid Bolster, Drop-Side Equalizer (AAR Type-A)
Truck Wheelbase	8' 0"
Wheel Size	40"
Traction Motors	D37 (4), EMD/GM
Traction Generator	D15C, EMD/GM
Auxiliary Generator	EMD/GM
MU (Multiple-Unit)	Optional
Dynamic Brakes	No
Gear Ratio	62:15
Tractive Effort/Starting	62,000 Lbs
Tractive Effort/Continuous	36,000 Lbs at 11.0 mph
Top Speed	65 mph

Production Roster

(Total Built = 489)

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Nashville, Chattanooga & St Louis	24-29	7433-7438	6031	7/1950-8/1950	6
Indiana Harbor Belt	8836-8845	8127-8136	E1136	1/1950	10
Chicago, Burlington & Quincy	9249-9260	8493-8504	E1196	5/1950	12
Chicago & Eastern Illinois	126-131	8882-8887	E1228	2/1950	6
Wabash Railroad	355-362	9037-9044	E1242	7/1950	8
Indiana Harbor Belt	8856-8876	9121-9141	4000	2/1950-4/1950	21
Kansas City Southern	1300-1301	9159-9160	4057	10/1950	2
Atlantic Coast Line	643-651	9173-9181	4002	4/1950	9
Indiana Harbor Belt	8877-8879	9215-9217	4000	4/1950	3
New York Central	8880-8883	9221-9224	4040	5/1950	4
New York Central	8884-8897	9418-9431	4040	5/1950-6/1950	14
Indiana Harbor Belt	8846-8850	9446-9450	E1136	1/1950-2/1950	5
New York Central	8851-8855	9451-9455	E1136	2/1950	5
Indiana Harbor Belt	8835	9460	E1267	10/1949	1
Great Northern	163-170	9569-9576	4005	3/1950	8
Chicago, Burlington & Quincy	9261-9268	9718-9725	4006	7/1950	8
Conemaugh & Black Lick	107-111	9752-9756	4007	6/1950	5
Louisville & Nashville	2245-2250	9772-9777	4009	3/1950	6
Kansas City Southern (Louisiana & Arkansas)	1310-1315	9792-9797	4008	1/1951	6
Louisiana Midland Railway	10	9798	6238	1/1951	1
Conemaugh & Black Lick	112-115	9915-9918	4011	9/1950	4
New York Central	8911-8921	9950-9960	4012	1/1951	11
Illinois Central	9300-9309	10032-10041	6008	2/1950-4/1950	10
Illinois Central	9400-9409	10042-10051	4016	4/1950-6/1950	10
Peoria & Pekin Union	406	10085	6001	2/1950	1
Peoria & Pekin Union	408-410	10086-10088	4024	8/1950	3
Peoria & Pekin Union	407	10116	6001	2/1950	1
St. Louis-San Francisco Railway (Frisco)	300-304	10182-10186	4028	12/1950-1/1951	5
Union Railroad	573-574	10235-10236	4041	11/1950	2
Detroit, Toledo & Ironton	920-922	10242-10244	4039	9/1950	3
Chesapeake & Ohio	5214-5239	10273-10298	6075	1/1950-3/1950	26
Clinchfield	350-353	10299-10302	6034	7/1950	4
Conemaugh & Black Lick	103-105	10303-10305	6020	12/1949	3
Pennsylvania	9364-9368, 9373-9395	10387-10414	6022	3/1950-5/1950	28
Pennsylvania	9358-9363, 9369-9372	10431-10440	4031	6/1950-7/1950	10
Chicago & Eastern Illinois (Chicago Heights Terminal & Transfer)	132-133	10526-10527	6039	6/1950	2
Union Pacific	1800-1824	10752-10776	4038	8/1950-11/1950	25
Detroit, Toledo & Ironton	923-924	10801-10802	4039	10/1950	2
Great Northern	11-13	10869-10871	6050	6/1950	3
Union Railroad	571-572	10898-10899	4041	11/1950	2
Northern Pacific	107-114	10932-10939	6054	11/1949-12/1949	8
Southern Railway (Cincinnati, New Orleans & Texas Pacific)	6060-6073	10942-10955	6056	2/1950-3/1950	14
Southern Railway (New Orleans & North Eastern)	6852-6863	10956-10967	6064	12/1949-1/1950	12
Southern Railway (Alabama Great Southern)	6505-6509	10968-10972	6065	1/1950-2/1950	5
Southern Railway (Georgia Southern & Florida)	8200-8203	10973-10976	6066	5/1950	4
Lehigh Valley	220	11185	6076	1/1950	1
Lakeside & Marblehead Railroad	12	11186	6077	3/1950	1
Arkansas & Louisiana Missouri Railway	11	11232	6085	3/1950	1
Louisville & Nashville	2251-2265	11301-11315	4047	12/1950	15
Cornwall Railroad	120-121	11372-11373	6087	3/1950	2
Philadelphia, Bethlehem & New England	31-32	11374-11375	6094	3/1950	2
Conemaugh & Black Lick	106	11376	6106	4/1950	1
Chicago & Illinois Western	101	11377	6088	4/1950	1
St. Louis Southwestern Railway (Southern Pacific)	1054-1057	11383-11386	6090	4/1950	4
Detroit & Toledo Shore Line	116-117	11399-11400	6092	4/1950	2
Milwaukee Road	1646	11401	4049	9/1950	1
Colorado & Southern Railway (Burlington)	154	11475	4050	8/1950	1
Missouri Pacific	9142-9146	11554-11558	6102	6/1950	5
Clinchfield	354-355	11623-11624	6034	7/1950	2
Central Railroad of New Jersey (Central Railroad Of Pennsylvania)	1080-1083	11629-11632	6108	5/1950	4
Illinois Central	9310-9319	11648-11657	4053	10/1950-12/1950	10
Illinois Central	9410-9429	11658-11677	4054	8/1950-12/1950	20
Detroit & Toledo Shore Line	118	11732	6092	4/1950	1
Chicago River & Indiana (New York Central)	8898-8903	11774-11779	4058	6/1950	6
Erie Railroad	428	11825	6120	5/1950	1
Nashville, Chattanooga & St. Louis	30-33	11924-11927	6031	8/1950	4
Texas & Pacific	1020-1023	11996-11999	6133	7/1950	4
Erie Railroad	429-430	12022-12023	4061	11/1950	2
Erie Railroad	432-433	12024-12025	4069	11/1950	2
Erie Railroad	431	12026	4070	11/1950	1
New York, Chicago & St. Louis (Nickel Plate Road)	230-232	12307-12309	6139	9/1950-10/1950	3
Maine Central	331-333	12370-12372	6148	9/1950	3
Lehigh Valley	221-224	12467-12470	4068	12/1950	4
Woodward Iron Company	50-51	12720-12721	6163	9/1950	2
Chicago & Illinois Western	102-103	12895-12896	6169	12/1950	2
Conemaugh & Black Lick	116-117	12917-12918	4011	10/1950	2
Peoria & Eastern (New York Central)	8904-8910	13012-13018	6174	11/1950	7
Youngstown & Southern	70-71	13019-13020	6175	11/1950	2
Montour Railroad	72	13021	6175	11/1950	1
Charleston & Western Carolina	800-801	13022-13023	6176	11/1950	2
Pennsylvania Railroad	8861-8868, 8871-8872	13063-13072	6230	1/1951	10
Kansas City Southern	1302-1309	13420-13427	4057	10/1950-11/1950	8
Louisville & Nashville	2266	13532	4047	12/1950	1
Cornwall Railroad	122	13540	6199	11/1950	1
Philadelphia, Bethlehem & New England	33-34	13565-13566	6201	9/1950-10/1950	2
Weyerhaeuser Timber Company	300-301	13571-13572	6225	12/1950-1/1951	2
Monessen Southwestern Railroad	21	13573	6211	10/1950	1
River Terminal	61-62	13674-13675	6233	1/1951	2
Phelps Dodge Corporation (New Cornelia Branch Mine)	6	13981	6241	1/1951	1
Detroit Terminal	116	14097	6239	1/1951	1

Sources

EMD. Operating Manual #2303: 600 & 1200 HP Switching Locomotives (Models SW1 & SW7; 567 Series Engines). La Grange: Electro-Motive Division (General Motors Corporation), January, 1950 (5th Edition).

Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.

Hayden, Bob. Diesel Locomotives: Cyclopedia, Volume 2 (Model Railroader). Milwaukee: Kalmbach Publishing Company, 1980.
Marre, Louis A. Diesel Locomotives: The First 50 Years, A Guide To Diesels Built Before 1972. Milwaukee: Kalmbach Publishing Company, 1995.

Pinkepank, Jerry A. Diesel Spotter's Guide. Milwaukee: Kalmbach Publishing Company, 1967.

Solomon, Brian. EMD Locomotives. Minneapolis: MBI Publishing Company, 2006.

Maine Central SW7's #333 and #331 carries out switching work in Bangor, Maine during June of 1980. American-Rails.com collection.

Instead, the company apparently decided to simply use the two letters as short for "Switcher." Once again, railroads were impressed with this latest EMD product and sales were strong.

Once again, the SW7 found use in yard work, light branch service, and a myriad of industrial applications. When production had ended some 489 units had been produced during only a two year production run.

It should noted that EMD also produced a cow/calf version of the SW7 known as the TR4. This model sold 15 total sets to the Santa Fe, Belt Railway of Chicago, Chesapeake & Ohio, and Milwaukee Road.

In his book, "Diesel Spotter's Guide," author Jerry Pinkepank notes the SW7 is distinguished from the SW9 and SW1200 by a single feature, an upper set of short vents on the carbody access doors. These are not present on the other two variants.