Alco "C-420" Locomotives: Roster, Specs, History

Last revised: December 26, 2024

American Locomotive's first 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.

As John Kirkland points out in his book, "The Diesel Builders: Volume Two," it was essentially an extension of the earlier RS32. Its specification became DL721A whereas the RS32 had been DL721.

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.

On a broader perspective, the C420 did prove one of Alco's more successful in the Century line and could be found on numerous railroads.

Interestingly, despite lukewarm sales, several C420s are preserved today. In addition, a handful even remain in freight service at various short lines around the country.

Photos

A pair of Lehigh Valley C420's and other Alco's roll through the west end of Allentown Yard during the 1970s; Allentown, Pennsylvania. American-Rails.com collection.

Overview

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 built on request), 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.

Interestingly, the largest buyer of C420s was the Pennsylvania-owned Long Island Rail Road, which owned thirty.

Reception

Once again, the C420 was more of a reactionary release by Alco in an attempt to remain competitive with newcomer General Electric and its U25B which debuted in 1959.

It's rather unfortunate that by the early 1960s Alco was generally 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.

Lehigh Valley C420 #410 is seen here at the engine terminal in Oak Island, New Jersey, circa 1970. Photographer unknown. American-Rails.com collection.

From a technical standpoint the 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 dominated the market with its 2,500 horsepower GP35 of 1963 (which would go on to sell well over 1,000 examples). 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.

Data Sheet and Specifications

Entered Production	6/1963 (Lehigh & Hudson River #21)
Years Produced	6/1963-8/8/1968
Model Specification	DL721A
Engine	251C, V-16
Horsepower	2,000
RPM	1,025
Carbody Styling	Alco
Length (Between Coupler Pulling Faces)	60' 3"
Weight	250,000 Lbs.
Dynamic Brakes	Optional
Trucks	B-B
Truck Type	Swing Bolster, Drop-Side Equalizer (AAR Type-B)
Truck Wheelbase	9' 4"
Wheel Size	40"
Traction Motors	GE 752 (4)
Traction Generator	GT581
Steam Generator	Optional
Gear Ratio	64:19 (80.5 MPH), 79:24 (82.5 MPH)
Tractive Effort Rating	57,200 Lbs.
Top Speed	82.5 MPH

Production Roster

Total Built = 131

Owner	Road Number(s)	Serial Number(s)	Date Built
Erie Mining Company	600-602	3437-01 thru 3437-03	12/1965
Lehigh & Hudson River	21, 22	84720, 84721	6/1963
Lehigh & Hudson River	23, 24	3431-01, 3431-02	12/1965
Lehigh & Hudson River	25, 26	3431-03, 3431-04	1/1966
Lehigh & Hudson River	27-29	3463-01 thru 3463-03	7/1966
Lehigh Valley	404-415	3385-01 thru 3385-12	10/1964
Long Island Rail Road	200-203	84722-84725	12/1963
Long Island Rail Road	204	84726	1/1964
Long Island Rail Road	205-207	84727-84729	2/1964
Long Island Rail Road	208	84779	2/1964
Long Island Rail Road	209, 210	84780, 84781	3/1964
Long Island Rail Road	211-214	84782-84785	4/1964
Long Island Rail Road	215-220	84786-84791	5/1964
Long Island Rail Road	221	3384-01	7/1964
Long Island Rail Road	222-229	6006-01 thru 6006-08	8/1968
Louisville & Nashville	1300-1305	3370-15 thru 3370-20	6/1964
Louisville & Nashville	1306-1313	3467-01 thru 3467-08	8/1966
Louisville & Nashville	1314, 1315	3467-09, 3467-10	9/1966
Mississippi Export	63	3425-01	9/1965
Monon Railroad	501, 502 (featured high, short hoods that housed steam generators)	3448-05, 3448-06	8/1966
Monon Railroad	503-506	3448-01 thru 3448-04	8/1966
Monon Railroad	507-518	3490-01 thru 3490-12	8/1967
New York, Chicago & St. Louis (Nickel Plate Road)	578	84792	6/1964
Norfolk & Western	413-420	3397-01 thru 3397-08	12/1964
Piedmont & Northern	2000, 2001	3430-01, 3430-02	12/1965
Seaboard Air Line	110-113	3418-01 thru 3418-04	5/1965
Seaboard Air Line	114-124	3418-05 thru 3418-15	6/1965
Seaboard Air Line	125, 126	3418-16, 3418-17	8/1965
Seaboard Air Line	127-135	3418-18 thru 3418-26	8/1965
Seaboard Air Line	136	3459-01	5/1966
Secretaría de Comunicaciones y Transportes (Mexico)	7123-10, 7123-11	3432-01, 3432-02	12/1965
Tennessee Central	400, 401	3438-01, 3438-02	1/1966, 2/1966

Sources

Foster, Gerald. A Field Guide To Trains. New York: Houghton Mifflin, 1996.

Kirkland, John F. Diesel Builders, The: Volume Two, American Locomotive Company And Montreal Locomotive Works. Glendale: Interurban Press, 1989.

Pinkepank, Jerry A. Diesel Spotter's Guide. Milwaukee: Kalmbach Publishing Company, 1967.

Solomon, Brian. Alco Locomotives. Minneapolis: Voyageur Press, 2009.

Long Island Rail Road C420 #206 was photographed here at the engine terminal in Jamaica, New York in 1964. At the time of this photo the locomotive was only a few months old. American-Rails.com collection.

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. Unfortunately, those in operation on short line Arkansas & Missouri (the fabled Alco line) have an uncertain future after the railroad announced in July it was acquiring three new SD70ACes and would retiring much of its Alco fleet.

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