Delaware and Hudson Alco RS11 No. 5004, August 1971. 

(Photo Roger Puta, Courtesy Marty Bernard, Public domain, via Wikimedia Commons)



The ALCO RS-11 is a class of diesel-electric locomotive rated at 1,800 hp (1.34 MW), that rode on two-axle trucks, having a B-B wheel arrangement. This model was built by both Alco (327 units) and Montreal Locomotive Works (99 units). Total production was 426 units.


Lehigh Valley 403, an Alco DL-701 or RS-11at Pittston, PA yard on June 29, 1969.

(Photo Roger Puta, Courtesy Marty Bernard, Public domain, via Wikimedia Commons)



The first three RS-11s were produced by ALCO in February 1956 as a demonstrator set. This locomotive, classified by ALCO as model DL-701, was their first high-horsepower road switcher, intended to be a 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. It was produced in high-nose and low-nose versions. Montreal Locomotive Works also built 351 nearly identical units, known as the RS-18, for the Canadian market.

While the RS-11 benefited from the increased power and reliability offered with ALCO's new 251B engine, and was arguably a more advanced product than the GP9, its market acceptance was disappointing against the reputation EMD's locomotives had made for superior reliability.


Apache Railway Alco RS11 901 at Snowflake, Arizona, February 16, 1981. Photographer: Peter Jobe.

(Public domain, Craig Garver, )


Original Owners

Railroad Quantity Numbers Notes
Alco 3 701, 701A, 701B
Carolina and Northwestern Railway 1 11
Chicago and Northwestern Railway 2 1613, 1624 RS-3s rebuilt by Alco in March 1960 as RS-11 with a 251-B engine but retained RS-3 high short hood.
Delaware and Hudson 12 5000-5011
Duluth, Winnipeg and Pacific 15 3600-3614
Erie Mining 15 300-314
Ferrocarril del Pacifico 1 1501
Ferrocarriles Nacionales de México 94 7200-7293
Green Bay and Western 1 309
Lehigh Valley Railroad 4 400-403
Maine Central 1 801
Ministry of Communication and Transportation (Mexico) 4 7123-1 - 7123-4
Missouri Pacific 12 4601-4612
Monongahela Connecting Railroad 1 700
New York, New Haven and Hartford 15 1400-1414
New York Central 9 8000-8008
New York, Chicago and St. Louis Railroad 35 558-577, 850-864
Norfolk and Western 99 308-406
Northern Pacific 18 900-917
Pennsylvania 38 8617-8654
Portland Terminal 1 1082
Seaboard Air Line 10 100-109
Southern Peru Copper Corp. 5 3-6, 8
Southern Pacific Railroad 34 5723-5729, 5845-5871
Toledo, Peoria and Western Railway 3 400-402
Total 431

Ferrocarril Sonora Baja California RS11 No. 2301 at Benjamín Hill, Sonora, Mexico in 1975.

(LIMO 5, CC BY-SA 4.0 <>, via Wikimedia Commons)




TPW 400, an RS-11 on display at Illinois Railway Museum, July 16, 2005.

(Photo by Sean Lamb (User:Slambo), CC BY-SA 2.0 <>, via Wikimedia Commons)



Type and origin
Power type: Diesel-electric
Builder: ALCO, MLW
Model: RS-11
Build date: February 1956 to June 1961 (Alco) /November 1957-1 unit, June 1963 to April 1964 (MLW)
Total produced: 431
​• AAR B-B
Gauge: 4 ft 8+1⁄2 in (1,435 mm) standard gauge
Trucks: AAR type B
Wheel diameter: 40 in (1,016 mm)
Minimum curve: 21° (274.37 ft or 83.63 m)
Wheelbase: 39 ft 4 in (11.99 m)
Length: 56 ft 6 in (17.22 m)
Width: 10 ft 1+5⁄8 in (3.089 m)
Height: 14 ft 5+1⁄8 in (4.397 m)
Loco weight: 257,300 lb (116,700 kg)
Fuel capacity: 2,000 US gal (7,600 L; 1,700 imp gal)
Prime mover: Alco 251B
RPM range: 1,000 rpm max.
Engine type: V12 Four stroke diesel
Aspiration: Turbocharger
Generator: GE GT 581
Traction motors: (4) GE 752
Cylinders: 12
Cylinder size: 9 in × 10.5 in (229 mm × 267 mm)
Performance figures
Maximum speed: 70–85 mph (113–137 km/h)
Power output: 1,800 hp (1,300 kW)
Tractive effort: 64,325 lb (29,177 kg)
Locale: North America South America


New Haven Railroad RDC No. 25, used for the New London - Worcester round trip, being shunted at New London by New Haven Alco RS-11 No. 1413.

RDCs were self-propelled, so the reason for it being shunted by a locomotive is unknown.

(Photo Roger Puta, Courtesy Marty Bernard, Public domain, via Wikimedia Commons)


FNM (Ferrocarriles Nacionales de México) Alco RS11 501 at Empalme, Sonora, January 6, 1995. Photographer: Paul Western. 

This is ex-Ferrocarril del Pacifico 501, repainted at the Emplame shops in the original FCP cream, green, reddish-brown, and black scheme.

The colors are reversed, originally the unit was painted mostly cream with green  accents, but FNM lovingly reproduced the color quite accurately.

(Craig Garver, Public domain,