After a successful first run of road switchers (The RS-1), Alco’s second attempt at a versatile four-axle locomotive came in late 1946. This was the stylized RS-2, keeping similar features as the RS-1 (Long carbody and short front nose), but with many upgrades. The most notable features were the rounded carbody and a new 244 prime mover, which increased the horsepower to 1,500, a 500hp upgrade over the RS-1. With the added horsepower, the RS-2 was received well by railroads for its ability to tackle any service it was given.

On a daily basis, one could see two RS-2’s powering a general merchandise freight, plying the hills with a loaded coal train coming back from the tipple, or running a passenger train at speed. The Delaware & Hudson would later retrofit their fleet with steam boilers and water tanks for passenger service. The Laurentian was one such service it powered, with dual RS-2’s and a striking lightning stripe consist. Alco and Canadian counterpart, Montreal Locomotive Works, successfully built over 370 of these versatile locomotives for railroads large and small. A good example was the Southern, Delaware & Hudson, and the New York Central ordered over 20 each, whereas the Birmingham Southern and the Texas and Pacific railroads both ordered just a single locomotive. The success of the RS-2 would later pave the way for the RS-3. Today, only a handful of prototypes exist, mostly in museums or on tourists operations.