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Alco "T-6" Locomotives


Last revised: March 23, 2024

By: Adam Burns

The T6 can be classified within the S series because the design is basically an S6 with an additional 100 horsepower and intended for use in slow, drag service (the "T" designation simply stood for Transfer switcher).

This type of locomotive dated back to the 1940s with the Baldwin Locomotive Works' DT-6-6-2000 and later RT624 models believing that there was a market for this type of switcher moving cuts of cars or freight over short distances (such as terminal operations or between yards).

However, the idea never really caught on as railroads saw little use for a such a specialized design believing (quite correctly) that standard switchers or small road switchers (like early Geeps and RS models) could perform that task just as well. 

From a broader perspective, Alco did have more success than Baldwin's models, which were simply too long, bulky and inefficient to be particularly useful. 

Today, at least four Alco T6s are preserved; Norfolk & Western #41 is the most notable, which is owned by the Roanoke Chapter of the National Railroad Historical Society.


91232735762357823894692468947.jpgChesapeake Western T6s #11 and #10 are seen here at work in Elkton, Virginia on August 27, 1979. Warren Calloway photo.


The American Locomotive Company (Alco), despite knowing of Baldwin's unsuccessful earlier models went ahead and released the T6 in late 1958 still believing that there would be a market for such a locomotive.

Even the Electro-Motive Division, the industry leader since main line diesels first hit the market in the late 1930s, understood that there was not a significant market for transfer switchers.

The Alco T6 debuted in March, 1958 and as can probably be guessed was most successful with industries and in mining applications including Brewster Phospahtes, Kaiser Steel, Portland Terminal Railroad, Newburgh & South Shore, and the Monongahela Connecting Railroad.

However, a few Class Is also found an interest in the model including the Norfolk & Western and Pennsylvania railroads purchased the T6. Additionally, Altos Hornos de Mexico, S.A. also picked up two units.

The T6 (which was designated by the company as its DL440) was almost identical to the S6 save for its notched number boards, a later Alco hallmark (particularly for the Century line) that no other model within the S series featured.

The T6 also differed from previous models in that it was a foot longer at 46 feet, 5 inches and also featured a slightly taller hood. Aside from these differences the transfer design was about the same internally; it featured a B-B truck setup using General Electric traction motors and generators as well as Westinghouse components.

Interestingly, the locomotive's tractive was a bit less than the S6; 60,000 pounds starting and 46,000 pounds continuous.


For the 57 examples of Alco T6s built they were apparently well liked, particularly by the Norfolk & Western, which purchased 40 of them. The N&W found them especially useful along the extreme eastern region of their system near the ports of Norfolk, Virginia.

There they were used for years shuffling empty and loaded coal hoppers, and other relevant freight, around the docks located there. Some of the units even continued to operate into the early Norfolk Southern years although all were retired soon afterwards. 

Data Sheet and Specifications

Entered Production3/14/1958 (Pennsylvania #8424)
Years Produced3/14/1955-1/10/1969
Model SpecificationDL440
Engine251B, 6-Cylinder In-Line
Carbody StylingAlco
Length (Between Coupler Pulling Faces)45' 5.75"
Height Above Rail Head14' 6"
Weight230,000 Lbs. or 248,000 Lbs.
Truck TypeGRS Rigid Bolster, Drop-Side Equalizer
Truck Wheelbase8'
Wheel Size40"
Traction MotorsGE 752 (4)
Traction GeneratorGT854
Gear Ratio74:18
Tractive Effort Rating46,000 Lbs. at 8 MPH.
Top Speed60 MPH

Production Roster

Total Built = 57

Owner Road Number(s) Serial Number(s) Completion Date
American Cyanamid 16, 17 3454-01, -02 6/1966, 7/1966
Kaiser Steel 1022, 1023 83392, 83393 12/1959
Monongahela Connecting 400 6004-01 7/1968
Newburg & South Shore 1016, 1017 6017-01, -02 1/1969
Norfolk & Western (Chesapeake Western) 10, 11 82309, 82310 1/1959
Norfolk & Western 12 - 21 82313-82322 2/1959-3/1959
Norfolk & Western 22 - 49 83364-83391 4/1959-10/1959
Pennsylvania 8424 - 8429 82857-82862 3/1958
Portland Terminal (Oregon) 46, 47 3489-01, -02 2/1968
Altos Hornos de México (AHMSA) 126, 127 3391-01, -02 12/1964

26293582936723986897384948728789.jpgPenn Central T6 #9844 (ex-Pennsylvania #8424) is seen here in Old Bridge, New Jersey on the New York & Long Branch, circa 1969. Fred Byerly photo. American-Rails.com collection.


Interestingly, despite the few T6s ever built there are actually numerous examples still operational aside from the one N&W unit preserved. 

These units include Middletown & Hummelstown #1016 is an original Newburg & South Shore unit; Arkansas & Missouri operates six, #12, #14, #16, and #18 are original N&W units while #15 and #17 are of Pennsylvania Railroad lineage; and International Terminals #9624. 

From a historical standpoint, the T6 was the final locomotive ever outshopped by the American Locomotive Company when Newburgh & South Shore Railroad #1016 and #1017 rolled out of the Schenectady plant in January, 1969. 


  • 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.


Wes Barris's SteamLocomotive.com is simply the best web resource on the study of steam locomotives. 

It is difficult to truly articulate just how much material can be found at this website. 

It is quite staggering and a must visit!