The SDP45 was a six-axle, C-C, 3,600-horsepower (2,680 kW) road switcher diesel-electric locomotive built by General Motors' Electro-Motive Division of La Grange, Illinois. It was a passenger-hauling version of the SD45 on a stretched locomotive frame with an extended, squared-off long hood at the rear, aft of the radiators, giving space for a steam generator for passenger train heating. This steam generator placement followed the pattern set by the SDP35 and SDP40.

BN 6597, showing the extended long hood aft of the radiators for the steam generator.
Type and origin
Power typeDiesel-electric
BuilderGeneral Motors Electro-Motive Division (EMD)
Build dateMay 1967 August 1970
Total produced52
Gauge4 ft 8 12 in (1,435 mm) standard gauge
Prime moverEMD 20-645-E3
Engine typeV20 diesel engine
Loco brakeIndependent air;
optional: dynamic brakes
Train brakesAir, schedule 26-L
Performance figures
Maximum speed100–109 mph (161–175 km/h)
Power output3,600 hp (2,680 kW)
LocaleNorth America

Original Owners

The Southern Pacific Railroad ordered their ten on May 9, 1966 with the units being placed in service between May 24 and July 26, 1967, initially on the City of San Francisco between Oakland and Ogden, and eventually used system-wide. As built, each unit carried 2,500 US gallons (9,500 l; 2,100 imp gal) of fuel and 3,000 US gallons (11,000 l; 2,500 imp gal) of steam generator water in a partitioned underframe tank. The steam generator was a Vapor Model OK-4740. SP's units had Pyle National Gyralights on the leading end, came with Nathan P-3 horns, and cost $317,156 each (SP's straight SD45's from the same period cost $290,788 each). Ordered with 62:15 gearing with the overspeed set at 72 mph (116 km/h), the gearing was changed to 60:17 (overspeed at 83 mph or 134 km/h) during 1968-1969. All except 3201 and 3207 would eventually be re-geared back to 62:15 once they entered commuter service. After Amtrak took over long-distance routes in 1971, various units were leased to Amtrak for West Coast service (primarily on the Coast Starlight) until Amtrak purchased their SDP40F locomotives, while the rest were used in freight service and on Company specials. Beginning in 1973 the SDP45s were used for commuter service on the San Francisco Peninsula Commute, replacing the Fairbanks-Morse Train Masters. SP's commuter service was demanding work and the locomotives required electrical modification to meet those demands. A "Passenger Start" switch was installed inside the cab electrical cabinet; in the "COMM" position the units were held in Parallel, in the "FRT/PASS" position normal transition was made. They stayed on the commute route (often working in freight service on weekends) until 1985 when Caltrain equipment arrived, and they were placed into freight service until their retirement, initially working out of Roseville, then in local and hauler service in the Los Angeles Basin. All were retired between 1986 (3208) and 1990 (3204) and sold for scrap.

The Great Northern Railway purchased eight SDP45s in 1967 to replace F-units on the Empire Builder. Normally paired back-to-back, they were also used singly leading F-units. These joined six smaller SDP40 locomotives ordered in 1966 for the Western Star. After the startup of Amtrak in 1971, Great Northern Railway successor Burlington Northern Railroad converted all fourteen SDP locomotives to freight service.

The Erie Lackawanna Railroad ordered 34 SD45Ms in 1969 and 1970. Intended for freight service, these units had standard (angled) long hood ends, the extra space aft of the radiators had concrete ballast. Their longer frames permitted a larger fuel tank which gave the locomotives a greater range between fuel stops.


OrderBuiltSerial NumbersQuantity1st No.2nd No.3rd No.Notes
79555/67-7/6732849-3285810SP 3200-3209Dispositions vary
79797/67-8/6733041-330488GN 326-333BN 9856-9863BN 6592-6599Dispositions vary
71745/69-6/6934976-3499419EL 3635-3653CR 6667-6684NS 6667-6684EL 3637 wrecked. Rest to CR and NS and eventually scrapped or traded in.
72467/70-8/7036658-366658EL 3654-3661CR 6685-6692VMVX 6685-6692May have been model SD45M, Dispositions vary
72468/7036880-368867EL 3662-3668CR 6693-6699VMVX 6693-6699May have been model SD45M, Dispositions vary


One Burlington Northern Railroad SDP45 (photo of BN 6599) was retrofitted with an articulated four-axle truck by EMD, converting it to an A1A-B+B wheel arrangement. The middle traction motor in the lead truck was removed and placed in the rear truck. The rear truck, called the HT-BB, for High Traction B+B arrangement, was tested successfully (closeup of HT-BB truck) but advances in traction motors obviated the need for four axle trucks. This testing was not related to the development of the HTCR three-axle radial truck first seen under SD60 EMD 3 and SD60MACs, and made standard on the early SD70 series.

Southern Pacific Railroad 8691-8696 were SD40M-2 rebuilds done by Morrison-Knudsen. They were ex-EL 3654, 3668, 3666, 3665, 3662 and 3659. It is this group that most surviving SDP45s belong to.

Erie Lackawanna 3637 was wrecked and rebuilt into a slug.


Erie Lackawanna Railroad 3639, later Conrail 6670, was listed as being preserved at the Virginia Museum of Transportation, although their collection listing does not show it. In August 2018, the Youngstown Steel Heritage group announced their intention to purchase 3639 and move it to their museum, with the goal of restoring it to operating condition, and eventually back to its original number and paint scheme.[1] In September 2018, the group announced that they have successfully purchased the locomotive.[2]


  1. "Extra 3639 North". FundRazr. Retrieved 2019-02-24.
  2. September 1; 2018. "Erie Lackawanna SDP45 to leave Virginia for Ohio | Trains Magazine". TrainsMag.com. Retrieved 2019-02-24.
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