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ALCO S-2 and S-4

🇺🇸 United States ·built by American Locomotive Company· from 1940· class of diesel locomotives

🛤️ diesel locomotive diesel
10 photos from Wikimedia Commons · credits & licences
  1. 1. GU 1001 S4: NJPolselli ( talk )· Public domain
  2. 2. Locomotive 1004 on Port Manatee Railroad, 1971 (cropped): Unknown author Unknown author· Public domain
  3. 3. ALCO S2 224 CYDZ Orlando FL: Meloaraujo· CC BY-SA 4.0
  4. 4. (Kewaunee) Green Bay and Western Railroad Power (27633372285): railfan 44· Public domain
  5. 5. ABL 105 (9232338283): sodai gomi· CC BY 2.0
  6. 6. ADMX ALCo S2 Switcher in Evansville, Indiana, Oct 2016: Dimensionpizza· CC BY 4.0
  7. 7. Alameda Belt Line's Alco S1 takes it easy over the weekend: sodai gomi· CC BY 2.0
  8. 8. ALCo S-2 -484 North Alabama Railroad Museum: Jeff Hunter from Madison, AL, USA· CC BY 2.0
  9. 9. 1524 calwa 1976x4 (33200097452): Drew Jacksich from San Jose, California Republic· CC BY 2.0
  10. 10. 20120324 097 Cargill Locomotive, Gilman, Illinois: David Wilson· CC BY 2.0
Read about it on Wikipedia ↗
ALCO S-2 and S-4, photo 1 of 10
1/10 NJPolselli ( talk )· Public domain

what is it?

The ALCO S-2 and S-4 are 1,000-horsepower (746 kW) diesel electric switcher locomotives produced by ALCO and Canadian licensee Montreal Locomotive Works (MLW). Powered by turbocharged, 6-cylinder ALCO 539 diesel engines, the two locomotives differed mainly in their trucks: the S-2 had ALCO "Blunt" trucks; the S-4, AAR type A switcher trucks. A total of 1,502 S-2s were built from August 1940 to June 1950; 797 S-4s were built from June 1949 to August 1957.

base stats

  • power 746 kWpower output
  • weight 104 tin working order
  • built 2,299made in total

Bars compare against all trains: 600 km/h (maglev), 1,700 seats; power, weight and number built on a log scale up to 20 MW, 1,000 t and 20,000 built.

fun facts

  • First built 86 years ago, in 1940.
  • 746 kW is about 9 family cars (~85 kW each) flat out.
  • Weighs about as much as 17 African elephants (~6 t each).
  • 14 m long: about 3 cars parked nose to tail.

diesel locomotive: A diesel engine on board drives the wheels, usually through a generator (diesel-electric).

spec sheet

built
1940–1957
number built
2,299
kind
Diesel-electric
traction
diesel
origin
🇺🇸 United States
builders
American Locomotive Company, Montreal Locomotive Works
top speed
—
power
746 kW
gauge
1,435 mm standard gauge
wheel arrangement
B-B
length
14 m
weight
104 t

From the Wikipedia infobox and Wikidata. Blank means the sources don't say.

Sources: Wikidata Q4652297, Wikipedia: ALCO S-2 and S-4 (CC BY-SA 4.0).Updated 2026-10-25.

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