EMD "SW1200" Locomotives: Data, Specs, Roster

Last revised: January 10, 2025

The SW1200 was pinnacle of Electro-Motive's switcher line featuring its 567 power plant. It was the final model to feature the engine and also the most successful with a total of 1,039 units produced between 1954 and 1966.

EMD's system for designating its switchers was not consistent, particularly in the early years, which makes deciphering each models' lettering and numbering somewhat difficult.

However, the SW1200 was a straightforward moniker with "SW" denoting "switcher" and 1,200 the horsepower rating. Once more, EMD enjoyed strong sales with this model as a variety of railroads and private industries purchased the locomotive.

Today, just as with virtually every other model in the series, SW1200's can continue to be found hauling freight for short lines and used in industrial settings, along with also pulling excursion trains.

Photos

Penn Central SW1200 #9199, still in its New Haven paint (built as #659) lays over in Maybrook, New York in the fall of 1970. Note Penn Central U25B #2672 in the background, also still in its New Haven paint (built as #2512). American-Rails.com collection.

Overview

The SW1200 began production in January, 1954 around the same time as its less powerful counterpart, the SW900. The model used EMD's 567C prime mover.

The 12-cylinder engine could produce a hefty 1,200 horsepower, which proved a strong selling point. At this rating the locomotive could be used in either switching work or even light freight duties. This latter ability was further enhanced by optional MU capabilities.

Using General Motors' newer model D37B traction motor the SW1200 could produce a respectable 36,000 pounds of continuous tractive effort and overall weighed just over 122-tons.

Baltimore & Ohio SW1200 #9618 wearing the Chessie System livery is seen here at Parkersburg, West Virginia on October 13, 1976. American-Rails.com collection.

Sales for the SW1200 quickly took off and with the builder's reputation at the time as the best locomotive manufacturer on the market, sales remained steady through the 1950s and even into the 1960s.

Just as with other SW series models, numerous Class Is, short lines, and private industries purchased the switcher. In his book, "Diesel Locomotives: Cyclopedia, Volume 2," Bob Hayden notes the SW1200 offered a variety of options including MU (as previously mentioned), sealed-beam headlight, additional rotating headlight, Flexicoil trucks, larger fuel tank, dynamic brakes, and dual controls.

Rio Grande SW1200 #135 lays over in Salt Lake City, Utah, circa 1975. Robert Eastwood, Jr. photo. American-Rails.com collection.

After EMD released the SW9 it abandoned cataloging its cow/calf TR series although it contemplated doing so with the SW900 of 1953 but ultimately decided against doing so.

In any event, the SW1200 would also not be offered in a cow/calf variant mostly because interest in the setup had waned following the SW9.

Domestic production on the switcher continued through May, 1966 and when the last unit was outshopped some 733 units (including a Great Northern rebuild) had been produced in the United States while another 274 were built by General Motors Diesel of London, Ontario (sometimes referred to as the SW1200RS).

Milwaukee Road SW1200 #711 (built as #2037) - the only switcher to wear the company's "Milwaukee II" livery - works the Miller Job at the Muskego Yard in Milwaukee, Wisconsin during March, 1985. R.W. Brown photo. American-Rails.com collection.

There were also another 32 units built for export in South and Central America including Brazil, Panama, and Chile.

Beginning with the SW1000, EMD swapped engines for the newer model 645 prime mover. In doing so the builder changed the carbody by featuring a hood with harder lines and less beveling, wider cab, and higher profile for improved visibility.

Data Sheet and Specifications

Entered Production	1/1954 (Milwaukee Road #1637-1642)
Years Produced (U.S.)	1/1954 - 5/1966
Years Produced (Canada)	9/1955 - 6/1964
EMD Class	SW1200
Engine	567C (12 Cylinder)
Engine Builder	EMD/GM
Horsepower	1200
RPM	800
Length	44' 5"
Height (Top Of Rail To Top Of Cab)	14' 6 1/2"
Width	9' 11 1/2"
Weight	245,000 Lbs
Fuel Capacity	600 Gallons
Air Compressor	WXO (Gardner-Denver)
Air Brake Schedule	26L (Westinghouse)
Trucks	B-B
Truck Type	GRS Rigid Bolster, Drop-Side Equalizer (AAR Type-A) or Flexicoil
Truck Wheelbase	8' 0"
Wheel Size	40"
Traction Motors	D37B (4), EMD/GM
Traction Generator	D15C, EMD/GM
Auxiliary Generator	EMD/GM
MU (Multiple-Unit)	Optional
Dynamic Brakes	Optional
Gear Ratio	62:15
Tractive Effort/Starting	74,000 Lbs
Tractive Effort/Continuous	36,000 Lbs at 11.0 mph
Top Speed	65 mph

Production Rosters

Electro-Motive (EMD)

(Total Built = 732)

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Milwaukee Road	1637-1642	18758-18763	4241	1/1954	6
Wabash	375-378	18877-18880	4243	1/1954	4
Wisconsin Central (Soo Line)	2120-2122	19085-19087	4289	1/1955	3
Southern Pacific (Texas & New Orleans)	113-118	19486-19491	4255	2/1954	6
Aliquippa & Southern	1201	19529	4282	6/1954	1
Bauxite & Northern	11	19530	4278	6/1954	1
Oliver Iron Mining Company	940	19531	4272	8/1954	1
Aliquippa & Southern	1202-1203	19532-19533	4282	6/1954	2
Oliver Iron Mining Company	941-942	19534-19535	4272	8/1954	2
Wheeling Steel	1254	19536	4287	10/1954	1
Oliver Iron Mining Company	943	19537	4272	8/1954	1
Soo Line	321	19538	4288	12/1954	1
Oliver Iron Mining Company	944-945	19539-19540	4272	8/1954	2
Soo Line	322-324	19541-19543	4288	12/1954	3
Coos Bay Lumber Company	1201-1203	19661-19663	4277	8/1954-9/1954	3
Milwaukee Road	2048-2061	20041-20054	4284	11/1954	14
Milwaukee Road	2020-2047	20055-20082	4286	11/1954-12/1954	28
Florida East Coast	229-235	20088-20094	4285	12/1954	7
Soo Line	325-327	20108-20110	4288	1/1955	3
Wisconsin Central (Soo Line)	2123-2127	20115-20119	4289	1/1955	5
Soo Line	328	20182	4288	1/1955	1
Northern Pacific	127-129	20320-20322	4290	7/1955-8/1955	3
Northern Pacific	119-121	20328-20330	4291	3/1955	3
Northern Pacific	122-125	20331-20334	4292	3/1955	4
Northern Pacific	126	20335	4293	3/1955	1
Weyerhaeuser Timber	304	20354	4294	2/1955	1
Chicago & Illinois Midland	18	20363	4295	4/1955	1
Wheeling Steel	1250, 1255-1257	20364-20367	4296	5/1955	4
Wheeling Steel	1258-1259	20368-20369	4299	5/1955	2
Chicago & Illinois Midland	19	20375	4295	4/1955	1
Grand Trunk Western	7017-7019	20381-20383	4300	4/1955	3
Grand Trunk Western	1505-1508	20413-20416	4270	5/1955-6/1955	4
Chicago, Burlington & Quincy	9271-9280	20543-20552	4302	9/1955-10/1955	10
Woodward Iron Company	52	20632	4307	8/1955	1
Simpson Logging Company	1200	20634	4309	4/1956	1
Simpson Logging Company	1201	20635	4340	5/1956	1
Aliquippa & Southern	1204-1207	20636-20639	4310	5/1955-8/1955	4
Tooele Valley Railway	100	20640	4311	5/1955	1
Terminal Railroad Association Of St. Louis	1219-1226	20656-20663	4313	7/1955-10/1955	8
Illinois Terminal	775-786	20666-20677	4316	11/1955-12/1955	12
Chicago & Illinois Midland	20-23	20678-20681	4317	11/1955	4
Rockdale, Sandow & Southern Railroad	8	20702	4318	10/1955	1
Point Comfort & Northern Railway	4	20703	4319	10/1955	1
Ashley, Drew & Northern	176	21016	4325	12/1955	1
Northern Pacific	130	21019	4327	1/1956	1
Norfolk & Portsmouth Belt Line	101-105	21021-21025	4328	12/1955-2/1956	5
Norfolk & Portsmouth Belt Line	106-115	21056-21065	4329	3/1956-6/1956	10
Great Lakes Steel	39	21082	4332	5/1956	1
Northern Pacific	133-134	21100-21101	4335	4/1956	2
Northern Pacific	131-132	21102-21103	4338	4/1956	2
New Haven	640-649	21165-21174	4334	1/1956-2/1956	10
Northern Pacific	135-140	21175-21180	4335	6/1956-7/1956	6
Northern Pacific	141	21181	4358	7/1956	1
Patapsco & Back Rivers	125-126	21242-21243	4336	4/1956	2
Northern Pacific	142-144	21433-21435	4358	7/1956	3
Bellefonte Central	5624	21471	4339	6/1956	1
New Haven	650-659	21473-21482	4334	2/1956-3/1956	10
Aliquippa & Southern	1208-1210	21559-21561	4341	2/1956-4/1956	3
Cuyahoga Valley Railroad	1280-1282	21598-21600	4343	5/1956	3
Philadelphia, Bethlehem & New England	39	21736	4344	6/1956	1
Great Lakes Steel	40	21737	4332	5/1956	1
Republic Steel Corporation	895	21818	4349	9/1956	1
Conemaugh & Black Lick	120-121	21831-21832	4351	6/1956	2
Patapsco & Back Rivers	127-129	22081-22083	4354	9/1956-10/1956	3
Steelton & Highspire	44	22084	4355	9/1956	1
Great Lakes Steel	41-42	22085-22086	4356	1/1957	2
Northern Pacific	145	22089	4358	7/1956	1
Patapsco & Back Rivers	130-134	22268-22272	4361	1/1957-4/1957	5
Inland Steel Corporation	88-89	22462-22463	4365	10/1956	2
Inland Steel Corporation	90-93	22464-22467	4368	2/1957	4
Great Northern	29-33	22481-22485	4369	4/1957-5/1957	5
Louisville & Nashville	2297-2300	22504-22507	4366	2/1957	4
Northern Pacific	146	22748	4373	2/1957	1
Northern Pacific	147-148	22749-22750	4379	2/1957	2
Northern Pacific	149-150	22751-22752	4380	2/1957	2
Northern Pacific	151-162	22753-22764	4374	6/1957-7/1957	12
Grand Trunk Western	1269-1270	22827-22828	4376	4/1957	2
Philadelphia, Bethlehem & New England	40-41	22903-22904	4381	1/1957	2
Southern Pacific (Texas & New Orleans)	123-128	22906-22911	4382	2/1957-3/1957	6
Aliquippa & Southern	1211-1213	23078-23080	4384	3/1957	3
Cuyahoga Valley Railroad	1283-1285	23081-23083	4385	3/1957-4/1957	3
Philadelphia, Bethlehem & New England	42-43	23266-23267	4381	1/1957	2
Wabash	379	23297	4389	1/1957	1
Great Lakes Steel	43-44	23301-23302	4391	4/1957	2
Baltimore & Ohio	9614-9621	23360-23367	4393	5/1957	8
Lake Superior Terminal & Transfer	105	23480	4396	7/1957	1
Middle Electric Coal Company	1201	23578	4400	6/1957	1
Delaware, Lackawanna & Western	561-568	23762-23769	4401	5/1957-6/1957	8
U.S. Steel	SX1-SX2	23770-23771	4402	8/1957	2
Oliver Iron Mining Company	946-947	946-947	4404	8/1957	2
Oliver Iron Mining Company	948	23785	4406	8/1957	1
Birmingham Southern	200-201	23983-23984	4408	7/1957	2
Inland Steel Corporation	94-96	23988-23990	4409	9/1957	3
Northern Pacific	163-177	24027-24041	4410	12/1957-1/1958	15
New Orleans Public Belt	71-72	24063-24064	4412	9/1957	2
Inland Steel Corporation	97-98	24090-24091	4413	3/1958	2
Pennsylvania	7900-7934	24132-24166	4414	11/1957-4/1958	35
Missouri-Kansas-Texas	1-6	24466-24471	4416	12/1957	6
Colorado & Southern	156-160	25006-25010	4425	2/1959	5
Fort Worth & Denver	607-610	25043-25046	4426	3/1959	4
Santa Fe	2439-2441	25224-25226	7573	6/1959	3
Inland Steel Corporation	103-104	25353-25354	4428	7/1960	2
River Terminal	63-64	25442, 25449	4429	5/1959	2
Republic Steel Corporation	362	25718	4435	12/1959	1
De Queen & Eastern	D-5	25731	4436	2/1960	1
Grand Trunk Western	1511-1519	25743-25751	4437	3/1960	9
Elgin, Joliet & Eastern	300-307	25847-25854	4439	5/1960-6/1960	8
Inland Steel Corporation	105-106	25913-25914	4428	7/1960	2
West Virginia Northern	52	26033	4440	8/1960	1
Chicago & North Western	310-315	26075-26080	7593	7/1960-11/1960	6
Great Lakes Steel	45	26156	4441	9/1960	1
Great Lakes Steel	46	26213	4443	10/1960	1
Great Lakes Steel	47	26779	4447	7/1961	1
Great Lakes Steel	16	27134	7618	3/1962	1
Chicago & North Western	316-321	27145-27150	7620	2/1962	6
Great Lakes Steel	48	27312	4451	4/1962	1
Minneapolis, Northfield & Southern	30-31	27507-27508	4452	9/1962	2
Missouri-Kansas-Texas	43-44	27800-27801	7633	10/1962	2
Reserve Mining Company	1212	27823	4453	12/1962	1
Missouri Pacific	1190-1199	27858-27867	7638	2/1963-3/1963	10
Missouri Pacific	1100-1125	27868-27893	7634	1/1963-4/1963	26
Ashley, Drew & Northern	178	28344	4455	6/1963	1
Belt Railway Of Chicago	524-526	23848-28350	7659	6/1963-7/1963	3
Reading	2715-2719	28412-28416	7664	11/1963	5
Great Lakes Steel	49	28676	4457	12/1963	1
Missouri Pacific	1126-1133	28747-28754	7693	1/1964-2/1964	8
Missouri Pacific	1179-1189	28755-28765	7701	2/1964-3/1964	11
Missouri Pacific	1175-1178	28766-28769	7707	2/1964	4
Missouri Pacific	1263-1264	28770-28771	7702	4/1964	2
St. Louis Southwestern Railway (Cotton Belt)	1062-1069	28895-28902	7696	1/1964	8
Minneapolis, Northfield & Southern	32-33	28933-28934	4459	2/1964	2
Inland Steel Corporation	107-108	28935-28936	4460	4/1964	2
Commonwealth Edison	16	29133	4462	7/1964	1
Kansas City Terminal	70-79	29239-29248	4463	6/1964-7/1964	10
Terminal Railroad Association of St Louis	1227-1233	29440-29446	7740	6/1964-8/1964	7
Great Lakes Steel	50-51	29483-29484	4465	7/1964	2
St. Louis Southwestern Railway (Cotton Belt)	1070-1073	29634-29637	7757	12/1964-2/1965	4
Southern Pacific	1597-1606	29638-29647	4469	12/1964-2/1965	10
Minneapolis, Northfield & Southern	34-35	29758-29759	4470	5/1965	2
Missouri Pacific	1265-1274	29780-29789	4473	1/1965-3/1965	10
Missouri Pacific	1152-1166	29790-29804	7766	3/1965-4/1965	15
Sandersville Railroad	200	29888	4472	12/1964	1
Terminal Railroad Association of St Louis	1234-1243	30004-30013	7779	4/1965-5/1965	10
Inland Steel Corporation	109-110	30014-30015	7780	12/1964	2
Rio Grande	130-134	30016-30020	4475	1/1965	5
Pacific Power & Light Company	10	30021	4476	1/1965	1
Rio Grande	135-139	30024-30028	4475	1/1965	5
Southern Pacific	1607-1623	30239-30255	4477	5/1965-11/1965	17
Peoria & Pekin Union	500	30307	4479	5/1965	1
Inland Steel Corporation	111-114	30486-30489	4480	6/1965	4
Cuyahoga Valley Railroad	1286	30490	4481	5/1965	1
Richmond, Fredericksburg & Potomac	84-85	30511-30512	7811	7/1965	2
Richmond, Fredericksburg & Potomac	81-83	30513-30515	7812	9/1965	3
Chicago, Burlington & Quincy	9281-9288	30533-30540	7804	6/1965-7/1965	8
Chicago, Burlington & Quincy	9289-9292	30541-30544	4482	7/1965-8/1965	4
Rock Island	920-928	30638-30646	4484	9/1965-10/1965	9
Great Lakes Steel	52-53	30738-30739	4485	10/1965	2
Rock Island	929-936	30743-30750	4484	10/1965	8
Missouri Pacific	1134-1141	31094-31101	7849	3/1966	8
Missouri Pacific (Texas & Pacific)	1280-1289	31110-31119	4491	3/1966	10
Missouri Pacific	1142-1151	31216-31225	7859	3/1966-5/1966	10
Missouri Pacific	1200-1201, 1255-1259, 1275-1279	31226-31237	4492	2/1966-3/1966	12
Missouri Pacific (Texas & Pacific)	1290-1299	31238-31247	4491	3/1966	10
St. Louis Southwestern Railway (Cotton Belt)	2289-2293	31570-31574	7867	1/1966-4/1966	5
Houston Belt & Terminal	34-37	31684-31687	4493	4/1966	4
Houston Belt & Terminal	33	31688	7877	5/1966	1

Pennsylvania SW1200 #9011 (Class ES-12) was photographed here in Columbus, Ohio, circa 1966. Fred Byerly photo. American-Rails.com collection.

EMD Rebuild

(Total Built = 1)

SW1200's completed from trade-in units, reusing the same serials as their predecessors.

Owner	Road Number	Serial Number	Order Number	Completion Date	Heritage	Quantity
Great Northern	100	647	7520	2/1955	Ex-Great Northern NC #5101.	1

General Motors Diesel (GMD)

(Total Built = 274)

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Canadian National	1593-1594	A740-A741	C191	9/1955	2
Canadian National	1595-1597	A742-A744	C191	2/1956	3
Canadian National	1575-1592	A745-A762	C190	3/1956-5/1956	18
Canadian Forest Products	301-302	A830-A831	C196	3/1956	2
Canadian National	1227-1247	A854-A874	C198	5/1956-9/1956	21
Canadian National	7020-7030	A875-A885	C201	9/1956-10/1956	11
Essex Terminal	105	A949	C210	3/1956	1
Roberval & Saguenay Railway	23	A976	C212	11/1956	1
Canadian National	1248-1268	A1020-A1040	C215	11/1956-3/1957	21
Canadian National	7031-7033	A1041-A1043	C216	1/1957	3
Canadian National	1271-1288	A1167-A1184	C228	8/1957-11/1957	18
Canadian National	1289-1304	A1358-A1373	C240	1/1958-5/1958	16
Canadian Pacific	8100-8130	A1480-A1510	C249	6/1958-10/1958	31
Canadian National	1305-1337	A1542-A1574	C253	7/1958-12/1958	33
Canadian Forest Products	303	A1715	C259	4/1959	1
Canadian Pacific	8131-8146	A1731-A1746	C261	4/1959-5/1959	16
Canadian National	1338-1357	A1788-A1807	C264	5/1959-7/1959	20
Canadian National	7034-7035	A1809-A1810	C265	7/1959	2
Canadian National	1358-1397	A1843-A1882	C273	4/1960-8/1960	40
Canadian Pacific	8147-8171	A1893-A1917	C275	7/1960-9/1960	25
Quebec Iron & Titanium/Chemin de fer de la Rivière Romaine (Romaine River Railway)	5	A1934	C282	5/1961	1
Dominion Foundries & Steel	14	A2047	C295	6/1964	1

Canadian units are sometimes referred to as SW1200RS, equipped with Flexicoil trucks.

Export

(Total Built = 32)

Owner	Road Number	Serial Number	Order Number	Completion Date	Quantity
Amapá Railway (Brazil)	1-3	20008-20010	701069-701071	1/1955	3
Chile Exploration Company (Chile)	911	23119	701453	2/1957	1
Chile Exploration Company (Chile)	912-913	23939-23940	701647-701648	9/1957	2
Chile Exploration Company (Chile)	914	25155	702021	4/1959	1
Chile Exploration Company (Chile)	915	25357	702022	7/1959	1
Chile Exploration Company (Chile)	916-917	25629-25630	702267-702268	11/1959-2/1960	2
Chile Exploration Company (Chile)	918-919	26652-26653	700057-700058	8/1961	2
Chile Exploration Company (Chile)	920-923	26769-26772	700164-700167	9/1961	4
Panama Canal Company (Panama)	661-663	27111-27113	700390-700392	6/1962-9/1962	3
Chile Exploration Company (Chile)	924-929	27456-27461	700432-700437	7/1962-8/1962	6
Chile Exploration Company (Chile)	930-935	28255-28260	700637-700642	3/1963	6
Amapá Railway (Brazil)	4	31838	710587	5/1966	1

Sources

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.

Milwaukee Road SW1200 #601 carries out switching chores at what appears to be the Bensenville, Illinois terminal on May 15, 1971. Photographer unknown. American-Rails.com collection.

Unfortunately, this 8-cylinder variant's slightly longer frame and higher cab caused clearance issues for private industries. As a result, EMD would release an updated version, the SW1001, to correct these flaws.

The SW1200's immediate successor was the 12-cylinder SW1500, a model that continued the success of its predecessor and saw more than 800 units produced at La Grange. Today's the powerful and versatile SW1200 is still quite common in industrial settings.

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