EMD SD40T-2
SP 8238 eastbound at Caliente, California, in the late 1980s
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
Specifications Configuration: ​  • 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) Loco 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) 82,000 lbf (360 kN) (continuous)
Career Operators Southern Pacific (and Cotton Belt), Rio Grande, Union Pacific Nicknames "tunnel motors" Locale United States Disposition most still in service as of 2010

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.^[1] 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.

Original purchasers

Preservation

• Denver and Rio Grande Western #5371 is preserved at the Utah State Railroad Museum in Ogden, Utah.^[2]

• Denver and Rio Grande Western #5401 is preserved at the Colorado Railroad Museum in Golden, Colorado.^[3]

• From 2010 to 2010, Union Pacific #2921 (formerly Southern Pacific #8385) was preserved at the Boone and Scenic Valley Railroad in Boone, Iowa.^[4] In 2020, the locomotive was traded to Midwest Locomotive Leasing (MWLX) for general service.