The ALCO DL420 was the prototype ALCO S-5 diesel-electric switcher locomotive. It was built in August, 1951 using an early six-cylinder 251 engine rated at 800 horsepower (600 kW) and RS-3 subassemblies in its construction.

Alco DL420 Image from: John Mech Collection; Refernce sources: A Centennial Remembrance: The American Locomotive Company; by Richard T. Steinbrenner Alco Historic Photos (Alco-GE Construction Number List) Extra 2200 South Railfan & Railroad Magazine Trains Magazine; Corrections / updates provided by: William MacClean and Romey Romagnoli

The ALCO 251 is a 4-stroke diesel engine that was developed by the American Locomotive Company to replace its 244 and 539 engines. The 251 was developed to be used in diesel locomotives, as a marine power plant in ships, and as a stationary power generator.

The American Locomotive Company (ALCO), based in Schenectady, New York, United States produced a wide range of diesel-electric locomotives from its opening in 1901 until it ceased manufacture in 1969. This is a list of ALCO locomotive classes. For individually notable locomotives, please see List of locomotives. There are numerous individual ...

May 31, 1998 · ALCo Diesel Locomotive Specification and Model Numbers ---- Switchers ---- Spec ... S2 S2 production subsequent to c/n 69219 E1530A S3 E1540A S4 E1540B S4 DL420 S5 S5 Prototype (ALCo-Schenectady Plant Switcher #6) DL421 S5 DL421A ...

Mar 15, 2023 · As you view the horsepower comparison chart covering ALCO diesels, you’ll see a variety of engine types from the McIntosh & Seymour 500 series to the 200 series that bear the ALCO name. Additionally, some of the M&S models have the letter T for “turbocharged”.

The ALCO DL420 was the prototype ALCO S-5 switcher diesel-electric locomotive. It was built in August, 1951 using an early six-cylinder 251 engine rated at 800 horsepower (600 kW) and RS-3 subassemblies in its construction.

It rode on two-axle trucks with a B-B wheel arrangement, and was the first ALCO switcher with a front radiator opening. This one-of-a-kind unit spent its time at the Niskayuna test facility, then at Schenectady as a shop switcher (#6).

American Locomotive Company (ALCO) produced a wide range of diesel-electric locomotives until it ceased manufacture in 1969. ALCO announced its "Century Series" of diesel locomotives in 1963 as a leap forward in power and reliability, an attempt to compete more aggressively with GM-EMD and GE in...

The ALCO Century 420 is a four-axle, 2,000 horsepower (1,491 kW) diesel-electric locomotive. 131 were built between June 1963 and August 1968. Cataloged as a part of ALCO's "Century" line of locomotives, the C420 was intended to replace the earlier RS-32 model.