SP 8238 eastbound at Caliente, California, in the late 1980s.

(Slambo at en.wikipedia, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons)



The SD40T-2 is a model of diesel-electric locomotive built by General Motors Electro-Motive Division in the United States. The SD40T-2 is equipped with a 16-cylinder EMD 645E3 diesel engine producing 3,000 horsepower (2,240 kW). 312 SD40T-2s were built for three railroads in the United States between April 1974 and July 1980. This locomotive and the SD45T-2 are popularly called tunnel motors, but EMD's term is SD40-2 with "cooling system modifications" because they were designed for better engine cooling in mountainous areas. The difference between this locomotive and its non-tunnel motor cousin, the SD40-2, are the radiator air intakes are located lower down at the rear of the locomotive.

This locomotive model was purchased by the Denver and Rio Grande Western Railroad, the Southern Pacific Railroad, and its subsidiary Cotton Belt. Southern Pacific's version has a 4,400-US-gallon (16,700 L; 3,660 imp gal) fuel tank and is 70 feet 8 inches (21.54 m) long. Rio Grande's version has a smaller 4,000-US-gallon (15,100 L; 3,330 imp gal) fuel tank.


Denver & Rio Grande Western EMD SD40T-2 5386 at Salt Lake City, Utah, August 21, 1984. Photographer: J R Quinn.

Retired by Union Pacific on December 28, 2000, and rebuilt in May, 2008, as FCA BB40T-2 4820 in Brazil.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/51151813536/)


Original purchasers

Railroad Quantity Road numbers Notes
Denver and Rio Grande Western Railroad 73 5341-5413 All with 81 in. or 88 in. short noses.
St. Louis Southwestern Railway (Cotton Belt) 10 8322-8326, 8372-8376 "snoot noses"
Southern Pacific Railroad 229 8230-8299, 8300-8321, 8327-8341 8350-8371, 8377-8391, 8489-8573 8300 series featured extended "snoot" noses for radio control equipment. 8278 was damaged beyond repair in the 1989 Cajon Pass runaway and sold for parts, then scrapped.
Totals 312

Southern Pacific EMD SD40T-2 8518 at Tucson, Arzona., circa 1983. Photographer Craig Garver.

(Craig Garver, Public domain, https://www.flickr.com/photos/digitalrailartist/50279494586/)



Type and origin
Power type: Diesel-electric
Builder: General Motors Electro-Motive Division
Model: SD40T-2
Build date: June 1974 – July 1980
Total produced: 312
​• AAR C-C
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Length: 70 ft 8 in (21.54 m)
Width: 10 ft 3 in (3.12 m)
Height: 15 ft 7.5 in (4.763 metres)
Locomotive weight: 368,000 lb (167,000 kg)
Fuel capacity: 4,400 US gal (16,700 L; 3,660 imp gal)
Prime mover: EMD 16-645E3
Engine type: V16 diesel
Cylinders: 16
Performance figures
Power output: 3,000 hp (2,240 kW)
Tractive effort: 92,000 lbf (410 kN) (starting)
Tractive effort: 82,000 lbf (360 kN) (continuous)
Operators: Southern Pacific (and Cotton Belt), Rio Grande, Union Pacific
Nicknames: "tunnel motors"
Locale: United States
Disposition: most still in service as of 2010