The ALCO RSC-2 was a

diesel-electric locomotive A diesel locomotive is a type of railway locomotive in which the prime mover 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 ...

that rode on three-axle

trucks A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame constructi ...

, having an

A1A-A1A The AAR wheel arrangement system is a method of classifying locomotive (or unit) wheel arrangements that was developed by the Association of American Railroads. Essentially a simplification of the European UIC classification, it is widely used in ...

wheel arrangement. 91 locomotives were produced — Used in much the same manner as its four-axle counterpart, the ALCO RS-2, though the wheel arrangement lowered the

axle load An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearin ...

for operation on light rail such as are found on

branch line A branch line is a phrase used in railway terminology to denote a secondary railway line which branches off a more important through route, usually a main line. A very short branch line may be called a spur line. Industrial spur An industr ...

s. The

Milwaukee Road The Chicago, Milwaukee, St. Paul and Pacific Railroad (CMStP&P), often referred to as the "Milwaukee Road" , was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until 1986. The company experienced ...

was the first railroad to take delivery of the RSC-2, initially assigning them to their Valley Division (headquartered near

Wausau, Wisconsin Wausau ( ) is a city in and the county seat of Marathon County, Wisconsin, United States. The Wisconsin River divides the city into east and west. The city's suburbs include Schofield, Weston, Mosinee, Maine, Rib Mountain, Kronenwetter, ...

) in November 1946. This was done in order to study the effects of an all-diesel roster (i.e. no steam locomotives available as a backup). The experiment was deemed a success and soon all steam locomotives were gone from the Valley Division. RSC-2s would faithfully serve the Milwaukee Road for many years, until being replaced in turn by the

EMD SDL39 The EMD SDL39 is a model of 6-axle diesel-electric locomotive built by General Motors Electro-Motive Division between March 1969 and November 1972. Power was provided by the EMD 645E3 12-cylinder engine as used in the EMD GP39 which generated 2, ...

. ALCO also exported these units to the state railway of

Portugal Portugal, officially the Portuguese Republic, In recognized minority languages of Portugal: :* mwl, República Pertuesa is a country located on the Iberian Peninsula, in Southwestern Europe, and whose territory also includes the Macaronesian ...

, where Portuguese Railways (CP) designated them Série 1500. These locomotives were built for the Iberian track gauge of (). The last units in Portugal served in regular passenger service into the first decade of the 21st century. Of these, five are still running today, 70 years after their arrival (one is a museum locomotive, while the other four are owned by track maintenance companies). Five units were exported to the Algerian National Railways where they were used in passenger train service.

Original Buyers

References

* {{ALCO diesels A1A-A1A locomotives RSC-2 Diesel-electric locomotives of the United States Railway locomotives introduced in 1946 Standard gauge locomotives of the United States 5 ft 6 in gauge locomotives Standard gauge locomotives of Algeria Diesel-electric locomotives of Portugal Diesel-electric locomotives of Algeria