The ALCO RSC-2 was a diesel-electric locomotive of the road switcher

Road switcher

A road switcher is a type of railroad locomotive used for delivering or picking up cars outside of a railroad yard. Since the road switcher must work some distance away from a yard, it needs to be able to operate at road speeds, it must also have high-visibility while it is switching, and it must...

 type that rode on three-axle trucks

Bogie

A bogie is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage/car or locomotive, or sprung as in the suspension of a caterpillar...

, having an A1A-A1A wheel arrangement.

Used in much the same manner as its four-axle counterpart, the ALCO RS-2

ALCO RS-2

The ALCO RS-2 is a , B-B road switcher railroad locomotive. It was manufactured by American Locomotive Company from October 1946 to May 1950, and 378 were produced — 369 by the American Locomotive Company, and 9 by Montreal Locomotive Works in Canada. Eight of the ALCO RS-2s were exported to...

, though the wheel arrangement lowered the axle load

Axle load

The axle load of a wheeled vehicle is the total weight felt by the roadway for all wheels connected to a given axle. Viewed another way, it is the fraction of total vehicle weight resting on a given axle...

 for operation on light rail such as are found on branch line

Branch line

A branch line is 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...

s.

The Milwaukee Road

Chicago, Milwaukee, St. Paul and Pacific Railroad

The Milwaukee Road, officially the Chicago, Milwaukee, St. Paul and Pacific Railroad , was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until its merger into the Soo Line Railroad on January 1, 1986. The company went through several official names...

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

Wausau, Wisconsin

Wausau is a city in and the county seat of Marathon County, Wisconsin, United States. The Wisconsin River divides the city. The city is adjacent to the town of Wausau.According to the 2000 census, Wausau had a population of 38,426 people...

) in November 1946. This was done in order to study the effects of an all-diesel roster (i.e. no steam locomotives available as protection power). 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

EMD SDL39

An EMD SDL39 is a 6-axle diesel locomotive built by General Motors Electro-Motive Division between March 1969 and November 1972. Power was provided by an EMD 645E3 12-cylinder engine which generated 2300 horsepower . All 10 examples of this locomotive model were built for Milwaukee Road, who wanted...

.

ALCO also exported these units to the state railway of Portugal

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

. The last units in Portugal served in regular passenger service well into the 21st century. Of these, five are still running today, 60 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

Railroad	Quantity	Road Numbers	Notes
ALCO (Demonstrator)	1	1190	to Union Pacific 1190 renumbered 1290
Caminhos de Ferro Portugueses Comboios de Portugal thumb|250px|right|CP suburban trains at São Bento Station in Oporto.CP — Comboios de Portugal, EPE is a state-owned company which operates freight and passenger trains in Portugal...	12	1501-1512	Uprated from 1500 hp to 2000 hp in 1976. Top speed was then 120 kilometres per hour (74.6 mph).
Chicago, Milwaukee, St. Paul and Pacific Railroad Chicago, Milwaukee, St. Paul and Pacific Railroad The Milwaukee Road, officially the Chicago, Milwaukee, St. Paul and Pacific Railroad , was a Class I railroad that operated in the Midwest and Northwest of the United States from 1847 until its merger into the Soo Line Railroad on January 1, 1986. The company went through several official names...	22	975–996	renumbered to 580-597, 490-493 series, not in order
Office des Chemins de Fer Algériens SNTF National company for rail transport is Algeria's national railway operator. The SNTF, a state-owned company, currently has a monopoly over Algeria's network of , even though it is currently exploiting only...	5	040DD1–040DD5
Seaboard Air Line Railroad Seaboard Air Line Railroad The Seaboard Air Line Railroad , which styled itself "The Route of Courteous Service," was an American railroad whose corporate existence extended from April 14, 1900, until July 1, 1967, when it merged with the Atlantic Coast Line Railroad, its longtime rival, to form the Seaboard Coast Line...	32	1500–1531
Soo Line Railroad Soo Line Railroad The Soo Line Railroad is the primary United States railroad subsidiary of the Canadian Pacific Railway , controlled through the Soo Line Corporation, and one of seven U.S. Class I railroads. Although it is named for the Minneapolis, St. Paul and Sault Ste...	4	368–371
Union Pacific Railroad Union Pacific Railroad The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....	10	1180–1189	renumbered 1280-1289