The Alco S1 was one of the first switcher models the company produced and debuted just after the company had released its first ever main line design, the DL series. The American Locomotive Company's history with switchers actually dated as far back as the boxcab design it had developed in conjunction with General Electric and Ingersoll-Rand in 1918 for the Jay Street Connecting Railroad (#4). In 1931 it began constructing more standard designs, the HH or "High Hood" switchers starting with the HH300. Along with this model Alco built the HH600, HH660, HH900, and HH1000 through July, 1940 producing 187 units in all. Convinced that it could successfully market a line of switchers, the builder released its "S" series (Switcher) soon after. Today, numerous S1s are preserved around the country, many of which are still operational.
The Alco S1 was first produced in 1940 featuring an end-cab design using McIntosh & Seymore's 539 model prime mover. The model came equipped with 600 horsepower and was well liked by short lines and Class Is for yard work and light branch line duties. The engine the S1 employed proved quite adept in this capacity although the builder would come to find that producing a reliable main line design was a far trickier task. This was mostly due to the fact that the Schenectady manufacturer did not see diesel locomotives as standard freight and passenger power, a fatal decision that would haunt the company for years. In any event, to its credit Alco correctly foresaw the demand for switchers, at least early with first-generation examples.
The S1 employed many design characteristics that the company had refined during its early years of collaborating with Ingersoll-Rand and GE, particularly during the construction of its HH line. This series was produced in conjunction with Westinghouse and McIntosh & Seymore featuring the former's "Visibility Cab" design, which was wider and, usually, taller (unless the hood was mounted flush with the top of the cab) than the trailing hood to give crews maximum visibility. Alco would make this cab the standard for its S series and early RS (Road Switcher) locomotives. The manufacturer also carried over the carbody design features Otto Kuhler had employed on the HH locomotives, primarily in the way of soft bevels and curves.
The Alco S1 was classed by Alco as its E1530 design and was quite similar to its later S3 model (actually, all of the S series locomotives were very similar in appearance, externally). It featured four, General Electric model 731 traction motors and also used main/secondary generators from the company. Additionally, Westinghouse supplied all air components (both companies supplied Alco with these parts virtually through the end of its time as a locomotive manufacturer). For a small switcher that only weighed 105 tons it could produce quite a bit of tractive effort; 57,500 pounds starting and 46,000 pounds continuous (a trait certainly not missed by railroads). For technical information on the S1 please click here.
A reliable and agile locomotive, railroads found the S1 incredibly useful. In all, the locomotive
would sell more than 500 examples to numerous Class I companies, smaller railroads, and a handful of private industries. Alco itself even used an S1 for switching duties at its
plant, #5. While the Montreal Locomotive Works also produced the S1 few
were built, just one was constructed for the Canadian Car &
Minitions located in Quebec. Additionally, foreign lines purchased the model
including Central do Brazil, National de Mexico, Polish State Railway,
and Margam Steel Works of Britian although amongst all four only 55 were
built. For more information about the S1 please refer to the chart above, which provides a full production roster of U.S. sales. To read more about other Alco switchers please visit the Diesel Locomotives section of the site, which can be reached from the top of this page.