Alco Diesel locomotive CFA 040 DD 1, Algeria.

(CFA image; collection Jean-Pierre Vergez-Larrouy, CC 3.0, via Wikimedia Commons)


Alco logo rectangular black & white.


The ALCO RSC-2 was a diesel-electric locomotive that rode on three-axle trucks, having an A1A-A1A 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 for operation on light rail such as are found on branch lines.

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

ALCO also exported these units to the state railway of Portugal, where Portuguese Railways (CP) designated them Série 1500. These locomotives were built for the Iberian track gauge of (1,668 mm (5 ft 5+21⁄32 in)). 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

Railroad Quantity Road numbers Notes
Caminhos de Ferro Portugueses (CP) 12 1501-1512 Designated Série 1500 by CP. Uprated from 1,500 horsepower (1,100 kW) to 2,000 horsepower (1,500 kW) in 1976. Top speed was then 120 km per hour (75 mph), the track gauge 1,668 mm (5 ft 5+21⁄32 in) . Four still in service.
Chicago, Milwaukee, St. Paul and Pacific Railroad 22 975–996 renumbered to 580–597, 490–493 series, not in order
Seaboard Air Line Railroad 37 1500-1536 1532-1536 rated at 1,600 hp (1,200 kW)
Soo Line Railroad 4 368–371 Soo had RS2 locos, which 368-371 were, no RSC2 locos were rostered.
Union Pacific Railroad 11 1180–1190 1190 was originally ALCO demonstrator 1190, all units later renumbered 1280-1290
Total 91

ALCO RSC-2 Overview

Type and origin
Power type: Diesel-electric
Builder: ALCO
Model: E-1661A, E-1661B, E-1661C
Build date: October 1946 – May 1950
Total produced: 91
Configuration: AAR A1A-A1A
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge; 1,668 mm (5 ft 5+21⁄32 in) (CP)
Wheel diameter: 40 in (1,016 mm)
Length: 53 ft 1 in (16.18 m)
Width: 10 ft 0 in (3.05 m)
Height: 14 ft 5 in (4.39 m)
Locomotive weight: 242,500 lb (110,000 kg)
Fuel capacity: 800 US gal (670 imp gal; 3,000 L)
Prime mover: Alco 244
Engine type: V12 Four-stroke diesel
Generator: DC generator
Traction motors: 4 of DC traction motors
Cylinders: 12
Transmission: Electric
Performance figures
Maximum speed: 65 mph (105 km/h)
Power output: 1,500 hp (1,100 kW); later models 1,600 hp (1,200 kW)
Tractive effort: 40,425 lbf (179,820 N)