BN 251, an EMD SW1200, works the yard in Eola, Illinois (just east of Aurora).

(Slambo at English Wikipedia, CC BY-SA 2.0 <>, via Wikimedia Commons)


EMD SW1200 Diesel-Electric Locomotive

An EMD SW1200 is a four-axle diesel switcher locomotive built by General Motors Electro-Motive Division between January 1954 and May 1966. Power is provided by an EMD 567C 12-cylinder engine, which generates 1,200 horsepower (890 kW). Additional SW1200 production was completed by General Motors Diesel in Ontario, Canada, between September 1955 and June 1964.

737 examples of this locomotive model were built for U.S. railroads, 287 were built for Canadian railroads, 4 were built for Brazilian railroads, 25 were built for a Chilean industrial firm, and 3 were built for the Panama Canal Railway.


Design and production

The SW1200 was the third model of 1,200 hp SW series switchers built by EMD. It was a successor to the SW7 and SW9. Compared to its direct predecessor, the SW9, the SW1200 differed in that it used the improved and more reliable 567C engine, compared to the SW9's 567B engine. Late SW1200s built in 1966 were instead built with the 567E 12-cylinder engine. Most of the locomotive's external features were unchanged from the SW9, making distinguishing between the two models difficult.

SW1200 production began in January 1954, immediately after SW9 production came to an end the previous month. Production continued for 12 years until the last SW1200 left EMD's manufacturing facility in May 1966.

Like many EMD products, customers could customize their SW1200 orders. Several options were available, including Flexicoil trucks. A few units were built with dynamic brakes, featuring a large square box with a fan on top of the hood, right in front of the cab.



A cow-calf variation, the TR12, was cataloged, but none were built.

An SW1200RS (RS for road switcher) is a variation of the standard SW1200 that features large front and rear (on some units) numberboard housings, EMD Flexicoil B-B trucks, and larger fuel tanks for road switcher service. The majority of the Canadian National and Canadian Pacific SW1200 fleets were purchased as SW1200RS units. SW1200RS units were produced near the end of SW1200 production in the mid-1960s.


Original buyers

Units built by Electro-Motive Division, United States

Railroad Quantity Road numbers Notes
Aliquippa and Southern Railroad 13 1201–1213
Amapa Railway 4 1-4 Brazil
Ashley, Drew and Northern Railway 2 176, 178
Atchison, Topeka and Santa Fe Railway 3 2439–2441
Baltimore and Ohio Railroad 8 9614–9621
Bauxite and Northern Railway 1 11
Bellefonte Central Railroad 1 5624
Belt Railway of Chicago 3 524–526
Birmingham Southern Railroad 2 200–201
Chicago and Illinois Midland Railroad 6 18–23
Chicago and North Western Railway 12 310–321 Acquired by EJ&E Railway then to Gary Railway (315 and 316 not part of GRW fleet)
Chicago, Burlington and Quincy Railroad 22 9271–9292 to Burlington Northern 229-250
Chicago, Rock Island and Pacific Railroad 17 920–936
Chile Exploration Company 25 911–935 Chile
Colorado and Southern Railway 5 156–160 to Burlington Northern Same
Commonwealth Edison 1 16
Conemaugh and Black Lick Railroad 2 120–121
Coos Bay Lumber Company 3 1201–1203 Built with dynamic brakes.
Cuyahoga Valley Railway 7 1280–1286
Delaware, Lackawanna and Western Railroad 8 561–568 to Erie Lackawanna 456–463
Denver and Rio Grande Western Railroad 10 130–139
De Queen and Eastern Railroad 1 D-5
Elgin, Joliet and Eastern Railway 8 300–307 300-301, 303-305 and 307 are now part of the Gary Railway Co. fleet per the 2009 CN acquisition of EJ&E Railway. 306 to LTEX 306
Florida East Coast Railway 7 229–235
Fort Worth and Denver Railway 4 607–610 to Burlington Northern Same
Grand Trunk Western Railroad 18 1269–1270, 1505–1508, 1511–1519, 7017–7019
Great Lakes Steel Corporation 16 16, 39–53
Great Northern Railway 6 29–33, 100 No. 100 Rebuilt from EMC NC2. All to Burlington Northern, 162-166
Houston Belt and Terminal Railway 5 33–37
Illinois Terminal Railroad 12 775–786
Inland Steel Company 27 88–114
Kansas City Terminal Railway 10 70–79
Lake Superior Terminal and Transfer 1 105
Louisville and Nashville Railroad 4 2297–2300
Midland Electric Coal Company 1 1201
Minneapolis, Northfield and Southern Railway 6 30–35 to Soo Line
Minneapolis, St. Paul and Sault Ste. Marie Railroad, ("Soo Line") 8 321–328 321, 323 and 324 were acquired by EJ&E Ry then part of Gary Ry Co. One unit acquired by Tulsa-Sapulpa Union Railway, now in active service as its Number 108.
Soo Line (Wisconsin Central Railroad) 8 2120–2127
Missouri Pacific Railroad 116 1100–1166, 1175–1201, 1255–1259, 1263–1279 Withdrawn in 1985 after the UP takeover. Sold to various owners or scrapped.
Missouri Pacific (Texas and Pacific Railway) 20 1280–1299
Missouri–Kansas–Texas Railroad 8 1–6, 43–44
New York, New Haven and Hartford Railroad 20 640–659 to Penn Central 9180-9199 and then Conrail 9363-9382
New Orleans Public Belt Railroad 2 71–72
Norfolk and Portsmouth Belt Line Railroad 15 101–115
Northern Pacific Railway 59 119–177 to Burlington Northern 170-228
Oliver Iron Mining Company 9 940–948
Pacific Power and Light 1 10
Panama Canal Railway 3 661–663
Patapsco and Back Rivers Railroad 10 125–134
Pennsylvania Railroad 35 7900–7934 To Penn Central
Peoria and Pekin Union Railway 1 500
Philadelphia, Bethlehem and New England Railroad 5 39–43
Point Comfort and Northern Railway 1 4
Reading Company 5 2715–2719 Equipped with 930 Gal. Fuel tanks
Republic Steel Corporation 2 362, 895
Reserve Mining Company 1 1212
Richmond, Fredericksburg and Potomac Railroad 5 81–85
River Terminal Railway 2 63–64
Rockdale, Sandow and Southern Railroad 1 8
Sandersville Railroad 1 200 renumbered 1200, upgraded to 12-645 spec
Simpson Logging Company 2 1200–1201 Built with Dynamic Brakes.
Southern Pacific Transportation Company 27 1597–1623 renumbered 2262-2288
Southern Pacific (Texas and New Orleans Railroad) 12 113–118, 123–128 renumbered 2213–2223
St. Louis Southwestern Railway ("Cotton Belt") 17 1062–1073, 2289–2293 1062-1073 renumbered to 2250-2261
Steelton and Highspire Railroad 1 44
Terminal Railroad Association of St. Louis 25 1219–1243
Tooele Valley Railway 1 100
U.S. Steel 2 SX1–SX2
Wabash Railroad 5 375–379
West Virginia Northern Railroad 1 52 Built with dynamic brakes.
Weyerhaeuser Timber Company 1 304
Wheeling Steel 7 1250, 1254–1259
Woodward Iron Company 1 52
Total 769

Units built by General Motors Diesel, Canada

Railroad Quantity Road numbers Notes
Canadian Forest Products 3 301–303 Flexicoil trucks, built with dynamic brakes
Canadian National Railway 208 1227–1268, 1271–1397, 1575–1597, 7020–7035 12/13/1500s have Flexicoil trucks and numberboards at both ends. Some units rebuilt to SW1200RMs
Canadian Pacific Railway 72 8100–8171 Flexicoil trucks, numberboards at front only
Dominion Foundries and Steel ("Dofasco") 1 14
Essex Terminal Railway 1 105
Quebec Iron and Titanium 1 5 Romaine River Ry
Roberval and Saguenay Railway 1 23
Total 287

Central Vermont SW1200 No. 1500 at White River Junction, VT yards on August 10, 1968.

(Photo by Roger Puta, Courtesy Marty Bernard, railfan 44, Public domain, via Wikimedia Commons)


Surviving and preserved units

This list is incomplete. Fremont and Elkhorn Valley Railroad 1219 built in March 1962 for Chicago & North Western is utilized for their excursion trains as well as the Fremont Dinner Train and currently pulls 1920s-era passenger cars for their non-profit excursion operations and the for-profit dinner train cars.



Type and origin
Power type: Diesel-electric
Builders: General Motors Electro-Motive Division; General Motors Diesel, Canada
Model: SW1200
Build date: January 1954 – May 1966
Total produced: 1,056
​• AAR B-B
• UIC Bo′Bo′
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge; 1,000 mm (3 ft 3+3⁄8 in) metre gauge, Chile; 5 ft (1,524 mm), Panama
4 ft 8+1⁄2 in (1,435 mm) standard gauge, Brazil
Prime mover: EMD 12-567C
Engine type: V12 diesel
Cylinders: 12
Performance figures
Power output: 1,200 hp (890 kW)
Locale: North America, South America
Disposition: Many scrapped, many still in use