Last revised: August 5, 2022
By: Adam Burns
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.
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.
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 SW7 was cataloged, the "SW" designation had changed: "S" no longer stood for six-hundred horsepower and "W" did not mean welded frame.
|Entered Production||10/1949 (Indiana Harbor Belt #8835)|
|Years Produced||10/1949 - 1/1951|
|Engine||567A (12 Cylinder)|
|Height (Top Of Rail To Top Of Cab)||14' 6"|
|Fuel Capacity||600 Gallons|
|Air Compressor||WXO (Gardner-Denver)|
|Air Brake Schedule||24EL (Westinghouse)|
|Truck Type||GRS Rigid Bolster, Drop-Side Equalizer (AAR Type-A)|
|Truck Wheelbase||8' 0"|
|Traction Motors||D37 (4), EMD/GM|
|Traction Generator||D15C, EMD/GM|
|Tractive Effort/Starting||62,000 Lbs|
|Tractive Effort/Continuous||36,000 Lbs at 11.0 mph|
|Top Speed||65 mph|
(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|
|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|
|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|
|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|
|Detroit, Toledo & Ironton||920-922||10242-10244||4039||9/1950||3|
|Chesapeake & Ohio||5214-5239||10273-10298||6075||1/1950-3/1950||26|
|Conemaugh & Black Lick||103-105||10303-10305||6020||12/1949||3|
|Chicago & Eastern Illinois (Chicago Heights Terminal & Transfer)||132-133||10526-10527||6039||6/1950||2|
|Detroit, Toledo & Ironton||923-924||10801-10802||4039||10/1950||2|
|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|
|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|
|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|
|Colorado & Southern Railway (Burlington)||154||11475||4050||8/1950||1|
|Central Railroad of New Jersey (Central Railroad Of Pennsylvania)||1080-1083||11629-11632||6108||5/1950||4|
|Detroit & Toledo Shore Line||118||11732||6092||4/1950||1|
|Chicago River & Indiana (New York Central)||8898-8903||11774-11779||4058||6/1950||6|
|Nashville, Chattanooga & St. Louis||30-33||11924-11927||6031||8/1950||4|
|Texas & Pacific||1020-1023||11996-11999||6133||7/1950||4|
|New York, Chicago & St. Louis (Nickel Plate Road)||230-232||12307-12309||6139||9/1950-10/1950||3|
|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|
|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|
|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|
|Phelps Dodge Corporation (New Cornelia Branch Mine)||6||13981||6241||1/1951||1|
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.