EMD SDP40

An SDP40 is a 6-axle passenger diesel-electric locomotive built by General Motors Electro-Motive Division (EMD) between June 1966 and May 1970.
==Design==
Like its predecessor in EMD's catalog, the SDP35, the SDP40 is a high-horsepower freight locomotive with equipment for passenger train service.
In 1966, EMD replaced all their production units with those powered by the new 645 diesel. They included six-axle models SD38, SD40 and SD45, in addition to SDP40. All had standard components including the frame, cab, generator, trucks, traction motors, and air brakes. The main difference was the power: the SD38 produced 2000 hp from a non-turbocharged V16, the SD40 produced 3000 hp from a turbocharged V16, and the SD45 produced 3600 hp from a turbocharged V20.
The SD40 and SDP40 were so similar that EMD published common operator's and service manuals to cover both.
At the time most passenger locomotives needed to provide steam to the passenger cars for heating, cooking, and sometimes cooling. They needed a higher gear ratio for faster running, the graduated-release feature on the air brakes, and type F tightlock couplers to keep equipment together in the event of a derailment. To fit a steam generator to the freight-only SD40, the designers had to move the machinery forward about 2 ft on the frame, add a compartment behind the radiators for the boiler, and divide the fuel tank into fuel and water sections.
==Appearance==
Earlier passenger diesels, like EMD E8, ALCO PA, FM Erie-built and Baldwin Sharknose locomotives, were streamlined cab units designed for visual appeal and the appearance of speed. The SDP40 and the SDP35 & SDP45 instead have the same appearance as their freight counterparts. This look was contemporary to, and eventually overtaken by cowl units like the GE U30CG and EMD FP45, SDP40F and F40PH.
Visually, the locomotive is a hood unit distinguished only by the shape of its rear end behind the radiators, with its flat end having no number boards, shuttered boiler air intake on each side, extra exhaust stacks over the boiler, cantilevered walkway around the flat end, and very steep rear steps. EMD applied this same end to the passenger SDP35, SDP45, and GP40P locomotives, as well as the freight DD35, DDA40X and SD40T-2.
Amtrak's SDP40F locomotive, although sharing several mechanical specifications, is visually a much different locomotive. Seven years separate their introductions, and the SDP40F was actually based on the SD40-2. It had a full-width carbody, similar to the FP45. It was also 6 ft longer than the SDP40.
==Original Owners==
Great Northern Railway (GN) purchased the first six SDP40s in 1966, to replace older E-units on their Western Star and smaller regional trains. Options included Vapor OK-4740 steam generators, water-transfer capability between units, 59:18 gearing for a top speed of 83 mph, and Type-F couplers. These were followed in 1967 by eight more powerful SDP45 locomotives ordered for the Empire Builder. After the startup of Amtrak in 1971, Great Northern's successor Burlington Northern Railroad (BN) converted the locomotives to freight service.
One SDP40, former GN 323, was temporarily renumbered BN 1976 and painted in red, white and blue for the United States Bicentennial in 1976.
NdeM had ten units delivered in 1968 and another four in 1970. In 1998, the government of Mexico privatized the NdeM the locomotives were split between two successor companies. Eight went to TFM, which was later purchased by Kansas City Southern Railway and became KCSM. Of those eight, two were rebuilt to SD22ECOs, and the other six were scrapped. The remaining six went to Ferromex. Of those six, four were rebuilt to SDP40-2s and remain in service, the other two were scrapped.
==Roster==
Order 	Built	1st No. 	Disposition
7870- 	5/66 	Great Northern Railway (U.S.) 320 	Scrapped MK Rail July 1996
7870-2	5/66 	Great Northern Railway (U.S.) 321 	Rebuilt, Active
7870- 	5/66 	Great Northern Railway (U.S.) 322 	Wrecked June 1984, scrapped
7870-4	5/66 	Great Northern Railway (U.S.) 323 	Rebuilt, Active
7870- 	5/66 	Great Northern Railway (U.S.) 324 	Stored Out-of-service - Reporting mark changed from BNSF to GN to make way for new deliveries
7870- 	5/66 	Great Northern Railway (U.S.) 325 	Wrecked August 1979 and rebuilt. Retired June 2008, donated to the Minnesota Transportation Museum May 2009. Active
710917	5/68 	Ferrocarriles Nacionales de México 8522	Scrapped December 2008 by Progress Rail in Mayfield, KY
710918	5/68 	Ferrocarriles Nacionales de México 8523	Scrapped
710919	5/68 	Ferrocarriles Nacionales de México 8524	
710920	5/68 	Ferrocarriles Nacionales de México 8525	
710921	5/68 	Ferrocarriles Nacionales de México 8526	
710922	5/68 	Ferrocarriles Nacionales de México 8527	
710923	5/68 	Ferrocarriles Nacionales de México 8528	Scrapped December 2008 by Progress Rail in Mayfield, KY
710924	5/68 	Ferrocarriles Nacionales de México 8529	Scrapped December 2008 by Progress Rail in Mayfield, KY
710925	5/68 	Ferrocarriles Nacionales de México 8530	Scrapped
710926	5/68 	Ferrocarriles Nacionales de México 8531	Rebuilt to SD22ECO August 2009
711392	5/70 	Ferrocarriles Nacionales de México 8532	
711393	5/70 	Ferrocarriles Nacionales de México 8533	Rebuilt to SD22ECO August 2009
711394	5/70 	Ferrocarriles Nacionales de México 8534	
711395	5/70 	Ferrocarriles Nacionales de México 8535	Scrapped
*
==Wrecks==
On August 23, 1979, BN 6399 was the lead unit of train 23 when it ran head-on into train 182 at Maiden Rock, WI. 6399 was repaired and returned to service, where it remained until its retirement, and it was eventually donated to the Minnesota Transportation Museum, where it still operates today. The four units of the other train were also repaired. The three trailing GP40 units were destroyed.
==Rebuilds==
*FNM 13099 was rebuilt by the San Luis Potosi shops, but the original locomotive number is unknown. The steam generator air intake was plated over during the rebuild.
*FXE 3227 appears to have been rebuilt from an SDP40, but the original locomotive number is unknown. The steam generator air intake was plated over during the rebuild, but it retained the full compartment and vertical rear steps.
*MRL 290 was wrecked in 1988, and subsequently sold to MRL. It is listed in rosters and lettered as an SDP40-2XR. Its steam generator air intake was plated over during the rebuild, but it retained the full compartment and vertical rear steps.
*GCFX 3093 sources suggest was remanufactured by Alstom to SD40-2 specifications. Much of the steam generator compartment was removed to permit installation of compliant rear switching steps.
*KCS 1319 was rebuilt by EMD in London, ON during August 2009 into an SD22ECO, keeping its external appearance.
*KCS 1320 was rebuilt by EMD in London, Ontario during August 2009 into an SD22ECO, keeping its external appearance.
==Preservation==
thumb|300x300px|BN SDP40 No. 325 at the Minnesota Transportation Museum In 2015
BNSF Railway donated #6327 - former Great Northern #325 and their last SDP40 in service - to the Minnesota Transportation Museum in May 2009. Since then, it has been in service on the Osceola and St. Croix Valley Railway. It has been repainted back to the Great Northern scheme as of 2023. 
== Gallery ==
File:KCS 3057.jpg|Kansas City Southern Railway #3057
==See also==
*GP40P
*List of GM-EMD locomotives
*List of GMD Locomotives
==References==
*Shine, Joseph W. (1992). Great Northern Color Pictorial - Volume 2: Division Assignment, Second Generation Diesels, The Big Sky Blue Era. La Mirada, CA: Four Ways West Publications. 
*Strauss, John F. Jr. (1998). Great Northern Color Pictorial - Volume 5: Rocky's Robe of Many Colors. La Mirada, CA: Four Ways West Publications. 
*The UNofficial EMD Homepage. Retrieved on May 1, 2009
*Sarberenyi, Robert. EMD's SD40, SD40A, and SDP40 - Original Owners. Retrieved on May 5, 2009
*Great Northern Empire - GN EMP SDP40 Roster. Retrieved on May 5, 2009
*KCS NAFTA Rosters. Retrieved on May 5, 2009
*Service Department (1966). SD40 - SDP40 Operator's Manual. La Grange, IL: Electro-Motive Division of General Motors Corporation
*EMD SD 6 WHEEL TRUCKS-DATA. Retrieved on July 25, 2010
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