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EMD SD39 BM690.jpeg
Boston & Maine 690 (ex Illinois Terminal 2301) with Train EDRJ (East Deerfield–Rotterdam Jct) about to enter Hoosac Tunnel
Power type Diesel-electric
Builder General Motors Electro-Motive Division (EMD)
Model SD39
Build date August 1968 – May 1970
Total produced 54
AAR wheel arr. C-C
Gauge 4 ft 8 12 in (1,435 mm)
Driver diameter 40 in (1,016 mm)
Length 65 ft 9 12 in (20.05 m)
Prime mover EMD 12-645-E3
Aspiration turbocharged
Cylinders V12
Power output 2,300 hp (1,720 kW)
Locomotive brake Independent air; optional: dynamic brakes
Train brakes Air, schedule 26-L
Locale United States

An SD39 is a 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division between August 1968 and May 1970. 54 were built for American railroads.

In 1966 EMD replaced all their old models with new ones having the new 645 diesel. These included six-axle models SD38, SD40, SDP40 and SD45; the SD39 was added in 1968. All shared standard components including the frame, cab, traction alternator, trucks, traction motors, and air brakes. The difference was the power output: SD38 = 2,000 hp (1,490 kW) from a non-turbocharged V16, SD39 = 2,300 hp (1,720 kW) from a turbocharged V12, SD40 = 3,000 hp (2,240 kW) from a turbocharged V16, and SD45 = 3,600 hp (2,680 kW) from a turbocharged V20. The SD39 had the smallest prime mover and therefore had the most unused space above the frame, inside the hood between the main generator and electrical cabinet, and outside in large end "porches".


A variant was the SDL39, ordered by the Milwaukee Road. Shorter and lighter than a stock SD39, these minimized weight per axle.

Original owners[1][edit]

Railroad Quantity Road numbers Notes
Atchison, Topeka and Santa Fe Railway
Illinois Terminal Railroad
4 went to Guilford Rail System, all have been scrapped.
Minneapolis, Northfield and Southern Railway
#40 currently used by Progressive Rail
Southern Pacific Transportation Company
Total 54

Dash 2 Rebuilds[edit]

On January 1, 1972 EMD debuted Dash 2 models. No SD39-2s were built as new units, but a number of SD39s were rebuilt to Dash 2 specifications.


  • Pinkepank, Jerry A. (1973). The Second Diesel Spotter’s Guide. Milwaukee, WI: Kalmbach Publishing Company. ISBN 0-89024-026-4. 
  • Trains Magazine Article December 1968, "A Market Oriented Catalog" by Wallace A. Abbey. The same article appears in Kalmbach's Our GM Scrapbook pages 82–83 subtitle, "Little diesel, big job".