The Alco S1 was one of the first model of switcher locomotive the company produced and debuted just after Alco released its first ever commercial locomotive design, the DL series. The American Locomotive Company's (Alco) history with diesel switchers actually dated as far back as the boxcab design it 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 beginning 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 catalog a successful line of switchers, Alco released the "S" series (Switcher) soon after, which would go on to be some of the most successful designs the manufacturer ever built. 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 diesel engine. The model came equipped with a 600 horsepower rating and were well liked by shortlines and Class Is for yard work and light branch line duties. The prime mover for the S1 proved to be quite adept in light duty although the builder would come to find that producing a reliable main line diesel engine was a far different story. This was mostly due to the fact that the Schenectady manufacturer did not see diesel locomotives being used in main line freight and passenger service. However, Alco correctly foresaw the demand for switchers, at least early on for first-generation diesels.
The Alco 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 use make this cab standard for its S series and early RS (Road Switcher) locomotives. The manufacturer also carried over the carbody design features of Otto Kuhler, which gave the HH models their final appearance, mostly in the way of soft bevels and curves.
The Alco S1 was classed by the builder 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 as well as main and 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 than only weighed 105 tons it could produce quite a bit of tractive effort; 57,500 pounds starting and 46,000 pounds continuous (which was something certainly not missed by railroads).
A reliable and agile locomotives, railroads came to find the S1 incredibly useful. In all, the Alco S1 model would sell more than 500 units to numerous Class I companies and smaller roads. 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 technical data of the S1 please click here. For a total production roster of Alco S1s please click here. Also, for more information about the S1 and all S series designs please refer to the chart below.
Alco S Series
|Model Type||Units Built||Date Built||Horsepower|
|S-5||7 (Built for B&M)||1954||800|
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