Southern Pacific EMD SDP45 No. 3207 leading Train No. 5 (the former San Francisco Zephyr) at Soda Springs, Nevada County, CA, January 1986.

(Drew Jacksich from San Jose, CA, The Republic of California, CC BY-SA 2.0 <>, via Wikimedia Commons)



The SDP45 is a six-axle, C-C, 3,600-horsepower (2,680 kW) 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.


EMD SDP45 locomotives leading the Great Northern Railway's Empire Builder ca. 1970-71.

(Great Northern Railway, Public domain, via Wikimedia Commons)


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 14 SDP45s in 1969 and 1970. Intended only for freight service, these units had standard (angled) long hood ends, and the extra space aft of the radiators had concrete ballast where a passenger unit would have a steam generator and venting. Their longer frames permitted a larger fuel tank which gave the locomotives a greater range between fuel stops. EMD later re-designated these as SD45Ms.


Erie-Lackawanna No. 3643, an EMD SDP45 at Hammond, IN yards on December 22, 1969.

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



Order Built Serial numbers Quantity 1st no. 2nd no. 3rd no. Notes
7955 5/67-7/67 32849-32858 10 SP 3200-3209 Model SDP45. All to NREX and presumed scrapped.
7979 7/67-8/67 33041-33048 8 GN 326-333 BN 9856-9863 BN 6592-6599 Model SDP45. BN 6599's rear truck was rebuilt as two B-type Flexicoil trucks giving the locomotive an A1A-B+B wheel arrangement, the only locomotive of its kind. All to LTEX and presumed scrapped.
7174 5/69-6/69 34976-34994 19 EL 3635-3653 CR 6667-6684 NS 6667-6684 Model SDP45, EL 3637 wrecked and rebuilt as a slug. Rest to CR and then to NS and eventually traded back to EMD for new SD60 locomotives.
7246 7/70 36658-36665 8 EL 3654-3661 CR 6685-6692 VMVX 6685-6692 Model SDP45. (later SD45M). All to VMVX and then rebuilt into SD40M-3 locomotives.
7246 8/70 36880-36886 7 EL 3662-3668 CR 6693-6699 VMVX 6693-6699 Model SDP45. (later SD45M). All to VMVX and then rebuilt as SD40M-3 locomotives.


One Burlington Northern Railroad SDP45 6599 was retrofitted with an articulated four-axle truck by EMD in 1983–84, 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 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 EMD SD60s and SD60MACs and made standard on the early SD70 series.

Southern Pacific Railroad 8691-8696 were SD40M-3 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.


Burlington Northern EMD SDP45 9857 at Cheyenne, Wyoming, February 16, 1974. Photographer: Bruce Black. (Craig Garver, Public domain,


Erie Lackawanna EMD SDP45 3661 at Scranton, Pennsylvania, May 13, 1973. Photographer: J. W. Hulsman. (Craig Garver, Public domain,

Conrail EMD SDP45 6673 at Chicago, Illinois, October 16, 1977. Photographer: J R Quinn. (Craig Garver, Public domain,


Erie Lackawanna Railroad 3639, later Conrail 6670, was listed as being preserved at the Virginia Museum of Transportation, although the museum's collection list does not show it. In August 2018, Youngstown Steel Heritage 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. In September 2018, the group announced that they had successfully purchased the locomotive. However, the current status of the project is unknown as the related pages have since been taken down.


Southern Pacific SDP45 No. 3206 with the Northbound Cascade at Berkeley station, April 1971.

(Drew Jacksich from San Jose, CA, The Republic of California, CC BY-SA 2.0 <>, via Wikimedia Commons)



Type and origin
Power type: Diesel-electric
Builder: General Motors Electro-Motive Division (EMD)
Model: SDP45
Build date: May 1967 – August 1970
Total produced: 52
​• AAR C-C
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Prime mover: EMD 20-645E3
Engine type: V20 diesel engine
Aspiration: turbocharged
Cylinders: 20
Locomotive brake: Independent air; optional: dynamic brakes
Train brakes: Air, schedule 26-L
Performance figures
Maximum speed: 100–109 mph (161–175 km/h)
Power output: 3,600 hp (2,680 kW)
Locale: North America