EMD SDP40


An SDP40 is a 6-axle passenger road switcher diesel-electric locomotive built by General Motors Electro-Motive Division 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: SD38 = from a non-turbocharged V16, SD40 = from a turbocharged V16, and SD45 = 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 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 longer than the SDP40.

Original Owners

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, 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 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

OrderBuiltSerialPhase1st No.2nd No.3rd No.4th No.5th No.6th No.7th No.8th No.Disposition
7870-
5/66
'
Ia2
Great Northern Railway 320
Burlington Northern Railroad 9850
Burlington Northern Railroad 6394
--
--
--
--
--
Scrapped MK Rail July 1996
7870-2
5/66
'
Ia2
Great Northern Railway 321
Burlington Northern Railroad 9851
Burlington Northern Railroad 6395
MRL 290
--
--
--
--
Rebuilt, Active
7870-
5/66
'
Ia2
Great Northern Railway 322
Burlington Northern Railroad 9852
Burlington Northern Railroad 6396
--
--
--
--
--
Wrecked June 1984, scrapped
7870-4
5/66
'
Ia2
Great Northern Railway 323
Burlington Northern Railroad 9853
Burlington Northern Railroad 6397
Burlington Northern Railroad 1976
Burlington Northern Railroad 6397
BNSF 6325
GCFX 3093
GRD 9043
Rebuilt, Active
7870-
5/66
'
Ia2
Great Northern Railway 324
Burlington Northern Railroad 9854
Burlington Northern Railroad 6398
BNSF 6326
GN 6326
--
--
--
Stored Out-of-service - Reporting mark changed from BNSF to GN to make way for new deliveries
7870-
5/66
'
Ia2
Great Northern Railway 325
Burlington Northern Railroad 9855
Burlington Northern Railroad 6399
BNSF 6327
Minnesota Transportation Museum 6327
Minnesota Transportation Museum Great Northern 325
--
--
Wrecked August 1979 and rebuilt. Retired June 2008, donated to the Minnesota Transportation Museum May 2009. Active
710917
5/68
'
IIb_
Ferrocarriles Nacionales de México 8522
Ferrocarriles Nacionales de México 8522
Transportación Ferroviaria Mexicana 1314
Kansas City Southern de México 1314
Scrapped December 2008 by Progress Rail in Mayfield, KY
710918
5/68
'
IIb_
Ferrocarriles Nacionales de México 8523
Ferrocarriles Nacionales de México 8523
Transportación Ferroviaria Mexicana 1315
Kansas City Southern de México 1315
Scrapped
710919
5/68
'
IIb_
Ferrocarriles Nacionales de México 8524
Ferromex ????
710920
5/68
'
IIb_
Ferrocarriles Nacionales de México 8525
Ferromex ????
710921
5/68
'
IIb_
Ferrocarriles Nacionales de México 8526
Ferromex ????
710922
5/68
'
IIb_
Ferrocarriles Nacionales de México 8527
Ferromex ????
710923
5/68
'
IIb_
Ferrocarriles Nacionales de México 8528
Transportación Ferroviaria Mexicana 1316
Kansas City Southern de México 1316
' December 2008 by Progress Rail in Mayfield, KY
710924
5/68
'
IIb_
Ferrocarriles Nacionales de México 8529
Transportación Ferroviaria Mexicana 1317
Kansas City Southern de México 1317
' December 2008 by Progress Rail in Mayfield, KY
710925
5/68
'
IIb_
Ferrocarriles Nacionales de México 8530
Transportación Ferroviaria Mexicana 1318
Kansas City Southern de México 1318
Kansas City Southern Railway 3057
Scrapped
710926
5/68
'
IIb_
Ferrocarriles Nacionales de México 8531
Transportación Ferroviaria Mexicana 1319
Kansas City Southern de México 1319
' to SD22ECO August 2009
711392
5/70
'
IIb2
Ferrocarriles Nacionales de México 8532
Ferromex ????
711393
5/70
'
IIb2
Ferrocarriles Nacionales de México 8533
Transportación Ferroviaria Mexicana 1320
Kansas City Southern de México 1320
' to SD22ECO August 2009
711394
5/70
'
IIb2
Ferrocarriles Nacionales de México 8534
Ferromex ????
711395
5/70
'
IIb2
Ferrocarriles Nacionales de México 8535
Transportación Ferroviaria Mexicana 1321
Kansas City Southern de México 1321
Scrapped

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, as were the four units of the other train. The three trailing GP40 units were destroyed.

Rebuilds

A consideration when rebuilding an SDP40 is that the rear corner steps do not comply with current Federal Regulations. The bottom step must be further out than the upper steps to provide a place to stand. Since the steam generator compartment extends to the end of the frame, it must be removed to install compliant switching steps. FXE 3212 and GCFX 3093 are examples. See:

The rebuilt into SD22ECOs took a different approach: The bottom steps of the rear ladders were moved out to meet the requirement.

Preservation

donated #6327 - former GN 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. The Museum has renumbered the locomotive back to 325 and, in the future, it will be repainted in the Great Northern "Big Sky Blue" paint scheme.