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TPW 400 20050716 Illinois Railway Museum.JPG
TPW 400, an RS-11 on display at Illinois Railway Museum, July 16, 2005.
Type and origin
Power type Diesel-electric
Builder ALCO, MLW
Model RS-11
Build date February 1956 to June 1961 (Alco) / April 1964 (MLW)
Total produced 425
AAR wheel arr. B-B
Gauge 4 ft 8 12 in (1,435 mm)
Trucks AAR type B
Wheel diameter 40 in (1,000 mm)
Minimum curve 21°
Wheelbase 39 ft 4 in (11.99 m)
Length 56 ft 6 in (17.22 m)
Width 10 ft 1 58 in (3.089 m)
Height 14 ft 5 18 in (4.397 m)
Locomotive weight 257,300 lb (116,700 kg)
Fuel capacity 2,000 US gal (7,600 L)
Prime mover ALCO 251B
Engine RPM range 1,000 rpm max.
Engine type Four stroke diesel
Aspiration Turbocharger
Generator GE GT 581
Traction motors (4) GE 752
Cylinders V12
Cylinder size 9 in × 10.5 in (229 mm × 267 mm)
Performance figures
Power output 1,800 hp (1,300 kW)
Tractive effort 64,325 lb (29,177 kg)
Locale North America South America

The ALCO RS-11 is a diesel-electric locomotive of the road switcher type rated at 1,800 hp (1.34 MW), that rode on two-axle trucks, having a B-B wheel arrangement.


The first RS-11s were produced by ALCO in early 1956. This locomotive, classified by ALCO as model DL-701, was their replacement for the very popular RS-3 road switcher. Featuring a V-12, 1,800 hp (1,300 kW) 251B diesel engine, the RS-11 was ALCO's answer to EMD's very successful GP9. The turbocharged RS-11 accelerated faster, had a higher tractive effort rating and typically used less fuel than the competition. It was also quite versatile and could be found in heavy haul freight as well as passenger service.

Original purchasers[edit]

The largest owner of RS-11s was Norfolk and Western Railway which purchased a total of 99 units (an additional 35 were added to the fleet after the merger with Nickel Plate Road). Other major purchasers included Northern Pacific Railway, Pennsylvania Railroad and Southern Pacific Railroad, all of whom placed repeat orders. With approximately 425 units built for the US and Mexico over 8 years of production, the RS-11 was successful for ALCO in that it provided ongoing competition for EMD's popular road switchers. A few examples of this model are still in service as of 2007 and can be found working for various short-line railroads in the US.

See also[edit]