The EMD GP15 is a 4-axle

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the power source is a diesel engine. Several types of diesel locomotives have been developed, differing mainly in the means by which mechanical power is conveyed to the driving whee ...

built by General Motors Electro-Motive Division between June 1976 and April 1983. Intended to provide an alternative to the rebuilding programs that many railroads were applying to their early road switchers, it is generally employed as a

yard The yard (symbol: yd) is an English units, English unit of length in both the British imperial units, imperial and US United States customary units, customary systems of measurement equalling 3 foot (unit), feet or 36 inches. Sinc ...

switcher A switcher locomotive (American English), shunter locomotive (British English), station pilot (British English), or shifter locomotive (Pennsylvania Railroad terminology) is a locomotive used for maneuvering railway vehicles over short distanc ...

or light

road switcher A road switcher locomotive is a type of railroad locomotive designed to both haul railroad car, railcars in mainline service and Shunting (rail), shunt them in railroad yards. Both type and term are North American in origin, although similar t ...

. There were 3 variants made: the GP15-1, the GP15T, and the GP15AC. The GP15-1 and GP15AC are powered by a 12-

cylinder A cylinder () has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infinite ...

EMD 645E engine, which generates . The GP15T differs in that it uses a turbo charged 8-cylinder instead of the roots blown 12-cylinder to generate the same horsepower. The GP15AC differs from the others as it uses an AC alternator connected to the engine instead of a DC generator to drive the traction motors. The radiator section is similar to those found on the

EMD SD40T-2 The SD40T-2 is a model of diesel-electric locomotive built by Electro-Motive Diesel, General Motors Electro-Motive Division in the United States. The SD40T-2 is equipped with a 16-cylinder EMD 645E3 diesel engine producing . 312 SD40T-2s were buil ...

and

EMD SD45T-2 The SD45T-2 is a model of diesel-electric locomotive built by EMD for the Southern Pacific Railroad. Like the later SD40T-2 it is colloquially nicknamed a tunnel motor. 247 total units (including the original EMD/SP joint-venture prototype) wer ...

"tunnel motors," leading some observers to incorrectly identify the units as such or as GP15Ts, and giving them the nickname "baby tunnel motors". A number of GP15-1s remain in service today for yard work and light road duty.

History and variants

GP15-1

The GP15-1 was the most popular variant as it did not contain either of the newer technologies of the other two variants (turbocharging or AC control). EMD built a total of 310 units for American railroads in this variant between June 1976 and March 1982. The

Missouri Pacific Railroad The Missouri Pacific Railroad , commonly abbreviated as MoPac, was one of the first railroads in the United States west of the Mississippi River. MoPac was a Class I railroad growing from dozens of predecessors and mergers. In 1967, the railroad o ...

purchased more units than the other three buyers combined. For spotting purposes, the MP models have a number of visually distinguishing features, though not all were applied consistently to the MP units: * The MP units have a grab iron ladder mounted on both sides of the long hood end; * MP's initial order of GP15-1s rode on Blomberg M trucks rather than the more common Blomberg B (all subsequent units were delivered with Blomberg B trucks) — and, while the standard Blomberg B truck carries two brake shoes per wheel, many MP units were equipped with only a single brake shoe per wheel; * #1555–#1574 were outfitted with the standard 81" nose, while the remaining units (all built in December 1976 or later) came with an 88" nose;

GP15T

EMD built 28 examples of a variant, the GP15T, between October 1982 and April 1983. It was a very close cousin to the GP15-1, but used a turbocharger in order to generate more power from a smaller engine. Power was provided by an 8-

diesel engine that generated , the same as the GP15-1, but with four fewer cylinders. 28 examples of this locomotive model were built for American railroads. The

Chessie System Chessie System, Inc. was a holding company that owned the Chesapeake and Ohio Railway (C&O), the Baltimore and Ohio Railroad (B&O), the Western Maryland Railway (WM), and Baltimore and Ohio Chicago Terminal Railroad (B&OCT). Trains operated u ...

received the majority of them as C&O 1500–1524 (25 units), while the rest went to the

Apalachicola Northern Railroad The Apalachicola Northern Railroad was a short-line railroad which operated in the Florida Panhandle of the United States. It owned and operated a between Port Saint Joe, Florida, and Chattahoochee, Florida, with a short spur to Apalachicola, Fl ...

in Florida as AN 720–722 (3 units).

GP15AC

The GP15AC is a variant built between November and December 1982. This model differs from the GP15-1 due to Missouri Pacific specifying new AR10 AC alternators instead of rebuilt D32 DC generators. The only external difference between the GP15AC and the GP15-1 is a straight side sill (shared with the

EMD GP15T The EMD GP15 is a 4-axle diesel-electric locomotive built by General Motors Electro-Motive Division between June 1976 and April 1983. Intended to provide an alternative to the rebuilding programs that many railroads were applying to their early ...

) not related to the transmission difference. 34 examples of this locomotive model were built in total: 30 for

, and four for Venezuela's IFE.

Rebuilds

Union Pacific has rebuilt 22 of their GP15-1's into GP15N's at their Jenks shop. These units received a microprocessor control system to increase adhesion, control options, and extend the life of the locomotive.

Preservation

In 2021,

CSX CSX Transportation , known colloquially as simply CSX, is a Railroad classes, Class I freight railroad company operating in the Eastern United States and the Canadian provinces of Ontario and Quebec. Operating about 21,000 route miles () of trac ...

donated GP15T #1507 (built 1982 as C&O #1507) to the

B&O Railroad Museum The B&O Railroad Museum is a museum and historic railway station exhibiting historic railroad equipment in Baltimore, Maryland. The Baltimore and Ohio Railroad (B&O) company originally opened the museum on July 4, 1953, with the name of the Balt ...

Baltimore, Maryland Baltimore is the List of municipalities in Maryland, most populous city in the U.S. state of Maryland. With a population of 585,708 at the 2020 United States census, 2020 census and estimated at 568,271 in 2024, it is the List of United States ...

. It is the first GP15 class locomotive to be preserved.

References

* * *

External links

EMD GP15T Operator's Manual
* Sarberenyi, Robert.

' {{DEFAULTSORT:Emd Gp15-1 B-B locomotives GP15-1 Diesel–electric locomotives of the United States Railway locomotives introduced in 1976 Freight locomotives Standard-gauge locomotives of the United States Chicago and North Western Railway locomotives Conrail locomotives St. Louis–San Francisco Railway locomotives