The AAR wheel arrangement system is a method of classifying locomotive wheel arrangements that was developed by the Association of American Railroads. Essentially a simplification of the European UIC classification, it is widely used in North America to describe diesel and electric locomotives. It is not used for steam locomotives, which use the Whyte notation instead.
The EMD SD70 is a series of diesel-electric locomotives produced by the US company Electro-Motive Diesel. This locomotive family is an extension and improvement of the EMD SD60 series. Production commenced in late 1992 and since then over 5,700 units have been produced; most of these are the SD70M, SD70MAC, and SD70ACe models. While the majority of the production was ordered for use in North America, various models of the series have been used worldwide. All locomotives of this series are hood units with C-C trucks, except the SD70ACe-P4 and SD70MACH which have a B1-1B wheel configuration, and the SD70ACe-BB, which has a B+B-B+B wheel arrangement.
The EMD SD40-2 is a 3,000-horsepower (2,200 kW) C-C diesel-electric locomotive built by EMD from 1972 to 1989.
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.
The EMD DD35 was a 5,000 horsepower (3,700 kW) diesel-electric locomotive of D-D wheel arrangement built by General Motors Electro-Motive Division for the Union Pacific Railroad and Southern Pacific Railroad.
The GE U50C was a 5,000 hp (3,700 kW) diesel-electric locomotive built by GE Transportation Systems. Each was powered by two 2,500 hp (1,860 kW) diesel engines.
The ALCO Century 855 was a model of 5,500 hp (4,101 kW) diesel-electric locomotive built in 1964 by the American Locomotive Company for the Union Pacific. The locomotive was notable for being ALCO's most powerful diesel-electric locomotive and, at the time, the most powerful diesel locomotive ever built, being surpassed by the 6,600-horsepower (4,922-kilowatt) EMD DDA40X in April 1969.
The EMD Dash 2 is a line of diesel-electric locomotives introduced by General Motors' Electro-Motive Division (EMD) on January 1, 1972. Designations of these models were those of the former models with "-2" added. They retained the basic specifications of the earlier models in terms of power output and most other features, but introduced a number of improvements to the locomotives' internal systems, specifically the electrical systems and the trucks of the locomotives. These were intended to improve availability, efficiency, and ease of maintenance.
The EMD SD50 is a 3,500-horsepower (2,610 kW) diesel-electric locomotive built by General Motors Electro-Motive Division. It was introduced in May 1981 as part of EMD's "50 Series"; production ceased in January 1986. The SD50 was a transitional model between EMD's Dash 2 series which was produced throughout the 1970s and the microprocessor-equipped SD60 and SD70 locomotives. A total of 431 were built.
The EMD SD40 is an American 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division between January 1966 and August 1972. 1,268 locomotives were built between 1966 and 1972. In 1972, an improved version with new electronics was developed and marketed as a new locomotive, the SD40-2.
An SDP40 is a 6-axle passenger diesel-electric locomotive built by General Motors Electro-Motive Division (EMD) between June 1966 and May 1970.
The SD45 is a six-axle diesel-electric locomotive class built by General Motors Electro-Motive Division between 1965 and 1971. It has an EMD 645E3 twenty-cylinder engine generating 3,600 hp (2,680 kW) on the same frame as the SD38, SD39, SD40, and SDP40. As of 2023, most SD45s have been retired, scrapped or rebuilt to SD40-2 standards.
The EMD SD38-2 is a model of six-axle diesel-electric locomotive built by General Motors Electro-Motive Division (EMD) from 1972 to 1979. EMD built 90 of these medium road-switchers, which were used in both yard and mainline roles. Part of the EMD Dash 2 line, the SD38-2 was an upgraded SD38 with modular electronic control systems, HT-C trucks, and many other detail improvements. The locomotive's power was provided by an EMD 16-645E 16-cylinder engine, which could generate 2,000 horsepower. These units were constructed with either 3,200 or 4,000 US gal fuel tanks and were available with or without dynamic brakes. It shared the same 64-foot-8-inch (19.71 m) frame as the SD40-2 and SD45-2, which gives it a length over couplers of 68 feet 10 inches (20.98 m).
The EMD SD45-2 is a 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division (EMD). EMD built 136 locomotives between 1972 and 1974, primarily for the Atchison, Topeka and Santa Fe Railway (ATSF). The SD45-2 was an improved version of the EMD SD45; the primary visual difference is the absence of flared radiators on the SD45-2.
The GE Dash 9-40CW is a 4,000-horsepower (3,000 kW) diesel-electric locomotive built by GE Transportation Systems of Erie, Pennsylvania, between January 1996 and December 2004. 1,090 were built for Norfolk Southern Railway, as road numbers 8889 to 9978. 53 GE Dash 8-44CWs built to Dash 9 specifications were also built for CSX Transportation, carrying road numbers 9000 to 9052.
The Baldwin RS-4-TC is a diesel-electric switcher locomotive built by the Baldwin-Lima-Hamilton Corporation between July 1953 and January 1955. The RS-4-TCs were powered by a supercharged twelve-cylinder diesel engine rated at 400 horsepower (298 kW), and rode on a pair of two-axle trucks in a B-B wheel arrangement. 74 of these models were built mainly for the Army while a few of them went to the Air Force.
The EMD G22 Locomotive Series made their debut in 1967 after the rise in popularity of the export EMD G12. Designed to meet most First World, Second World and Third World country requirements, the G22 Series was equipped with a naturally aspirated EMD 645 Series engine as well as four axle Flexicoil Type-B trucks which carried a low per-axle weight. Based on customer input, the G22 Series was defined by various designations that suited the customer's railway operations.
The EMD G22C Series were first introduced in 1968 to replace the popular G12 along with various improvements. They carried a low per axle weight on their Flexicoil Type-GC trucks and were the first model series to have a low nose as a standard option as well.
The EMD GT22 Series were first introduced in 1972 after the rise in popularity of six axle locomotives. The GT series now carried a turbocharger that increased the horsepower depending on customer input. The GT series also utilized six axle HTC Trucks, which allowed the locomotive to haul heavier loads at slower speeds with minimal wheelslip.
The EMD GT26 Locomotive Series made their debut in 1967 after the rise in popularity of the American EMD SD40. Designed to meet most First World, Second World and Third World countries, the GT26 Series were now equipped with a turbocharged high horsepower EMD 645 Series engine as well as six axle HT-C trucks to provide better traction effort at slow speeds. Based on customer input, the GT26 Series would be defined by various designations that suit the customer's railway operations.
