The Alco C420

One of the first of the American Locomotive Company's (Alco) new Century models was the C420. It was a four-axle design that offered sufficient horsepower. However, to some extent Alco continued to catalog custom models when a universal design would have sufficed, such as what EMD and General Electric had been doing for years (particularly the former). For instance, the C420 was meant to be a less powerful version of the C424, which was being produced at the same time. The Alco C420 had modest sales but the first design of the Century series did little to improve Alco's standing in the locomotive manufacturer's race. Interestingly, despite lukewarm sales numerous C420s are preserved today and several remain in operation on shortlines, nearly 50 years since the last was outshopped.

Delaware & Hudson C420s #405 and #407 along with a pair of RS11s and a GP39-2 head eastbound out of Buffalo, New York at William Street with train BM-4 on November 7, 1982.

The Alco C420 used the builder's new 261C prime mover that was much more reliable over its earlier designs. The model began production in June of 1963 and as was the case with late RS designs, the C420 featured a standard low nose (high nose units were only built on request, and some were built on the C420 model), similar to the Standard Cab design first employed by EMD on its GP30 model. As the designation suggests (which was a completely new system unveiled by Alco whereby the "C" stood for Century, "4" regarded the number of axles, and "20" referred to the horsepower), the C420 was capable of producing 2,000 horsepower and found buyers among a number of Class I railroads such as the Lehigh Valley, Norfolk & Western, Louisville & Nashville, and Monon. Interestingly, the largest buyer of C420s was the Pennsylvania-owned Long Island Rail Road, which owned thirty.

Once again, the C420 was more of a reactionary model released by Alco in an attempt to remain competitive with newcomer General Electric and its U25B released in 1959. It's rather unfortunate that by the early 1960s Alco was looked upon with resignation by the industry as the Century series, particularly the four axle models, were quite adept locomotives which were very reliable. Additionally, they continued to offer incredible pulling power (an Alco trademark) and fuel efficiency. Surprisingly, despite GE now being an Alco competitor, the Schenectady manufacturer continued to purchase from its one-time ally internal components as it always had such as traction motors and generators.

From a technical standpoint the Alco C420 was meant to replaced the RS32 model and while it offered less starting tractive effort (57,200 pounds) provided more continuous effort (38,000 pounds). Interestingly, neither Alco nor GE sold many models during the mid-1960s as EMD was once again dominating the market with its 2,500 horsepower GP35 of 1963 (which would go on to sell well over 1,000 examples).

BC Rail C420 #631 and yard slug #S407 are seen here in North Vancouver, British Columbia on May 21, 1992.

By the time production had ended in 1968 only a little over 100 Alco C420s had been built. However, aside from the large Class Is who purchased the model several smaller lines did as well such as the Piedmont & Northern, Tennessee Central, Lehigh & Hudson River, Erie Mining, Mississippi Export, and even the Secratario de Communicaciones Y Transportes of Mexico. Perhaps most fascinating with this model, in terms of its history, is how many continued to find usefulness in freight service long after they were sold by their original owner. Today, close to 40 of this relics remain preserved with the most famous in operation on the Apache Railway. For a total production roster of Alco C420s please click here. Also, for technical information on the model please click here. Finally, for more information about the C420 and all Century series designs please refer to the chart below.

Century Series

Model Type Units Built Date Built Horsepower
C-415261966-19681,500
C-4201311963-19682,000
C-4241901963-19672,400
C-425911964-19662,500
C-430161966-19683,000
C-6281861963-19682,750
C-6301331965-19693,000
C-636831967-19683,600
C-643H3 (Built For SP)19644,300
C-8553 (Built For UP)19645,500



Norfolk & Western C420 #417 is seen here in Brewster, Ohio on June 24, 1975. The N&W tried out several of Alco's diesel models but ultimately only purchased eight of its own C420s new in 1964, #413-420.

For a comprehensive look at the American Locomotive Company and all of the motive power types it built from steam, diesel, to electrics consider the book Alco Locomotives by Brian Solomon. Covering more than 175 pages Mr. Solomon's book details the history of Alco from its esteemed 4-6-4 Hudsons and 4-6-6-4 Challengers to vaunted RS and PA series diesel locomotives. If you have any interest in Alco this book is a must have!  Also consider Mike Schafer's Vintage Diesel Locomotives which looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic Alcos, or diesel locomotives in general, this book gives an excellent general history of both. If you're interested in perhaps purchasing either (or both) of these books please visit the links below which will take you to ordering information through Amazon.com, the trusted online shopping network.

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