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The Alco RS Series, The Classic Road Switcher

Aside from the PA, the Alco RS series of locomotives is likely what the venerable locomotive builder is best remembered for. Along with their popularity with the railfans and enthusiasts the RS series was very well liked by railroads, especially for branchline or yard service work (not to mention that it was very reliable). The model, aside from Alco's earlier S series of switch engines, was the manufacturer’s most popular, with over 2,000 units built between 1941 until production ended in 1960.

The Alco RS series debuted in 1941 as a step up from their popular S series of switchers (which came in S1, S2, S3 and S4 versions), which began production a year earlier in 1940. Mechanically there was little difference between the S series and the original RS1 except for a lengthened hood, which was used to accommodate a steam generator if requested by the railroad. The RS’s strengths were its flexibility and durability as it could be employed in all sorts of tasks from passenger operations to pulling freights and working in yard service. They were not particularly powerful at less than 2,000 horsepower but they were very resilient, so much so that many continued to be used even today!

The original RS1 most resembles its shorter predecessors, the S series even in its carbody, which carries the same sharp angles as the switcher models. Rated at only 1,000 horsepower and plainly labeled by their manufacturer (Road Switcher, 1st model), they quickly caught on with the railroads and lasted in Alco’s catalog until 1960, longer than both the later RS2 and RS3 models, with over 400 eventually built. Alco also built a C-C version of the RS1 known as the RSD1 but the six-axle version never quite caught on like its four-axle cousin, although interestingly a few of these continue to remain in use today.

Following the original RS1 model was the RS2 and RS3. These later models are perhaps Alco’s most popular, rating right up there with the company’s iconic PA design. Visually, while overall similar in design to the RS1, they are quite distinct in having much more rounded and softer angles. With a bit more horsepower than the RS1, the RS2 and RS3 come rated in either 1,500 or 1,600 hp and were extremely popular, even more so than the RS1.

Production for the Alco RS series, the RS2 and RS3, ranged for a decade between 1946 and 1956 but in that time well over 1,500 of the units were sold to several different railroads and employed in all sorts of tasks, much like the RS1. Also like the RS1, Alco featured C-C versions of the later models known as RSD4s and RSD5s, as well as A1A (two powered outside axles and an unpowered center axle) versions known as RSC2s and RSC3s. However, like the RSD1 all did not sell very well and few if any can be found today, even in museums or on static display.

While the RS1 is a bit harder to find, the RS2 and RS3 models continue to be very popular in the Alco RS series. However, they have long since disappeared on Class I rosters and to see them in action you will need to seek out one of the many shortlines or tourist lines, which continue to operate them.

For more information on the Alco RS series consider Mike Schafer’s Vintage Diesel Locomotives which looks at virtually all of the classic builders and models from Alco PAs to early EMD Geeps. If you’re interested in classic Alcos, or diesels in general, this book gives an excellent general history of both.

Also, Brian Solomon’s The American Diesel Locomotive also studies many of the same diesel models and builders as Mr. Schafer’s publication although at nearly twice the size the book goes into a bit more detail than Vintage Diesel Locomotives. All in all, though, both books are a great read and you shouldn’t be disappointed with them, not to mention that they are loaded with photos (many in color)! If you're interested in perhaps purchasing these books please visit The Railroad Diamond by clicking the tab in the menu to your left marked "TRD Store".

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