Nearly identical to the S2 switcher except for its AAR trucks, Alco's S4 found work on railroads large and small. Like cats with 9 lives, many of these rugged switchers have worked for multiple owners and dozens survive today. Featuring some of our most popular road names, we're sure one could find work on yours as well. The S4 features fixed trucks and a single-motor drive, with all axles powered.