Production of the RS-2 was delayed several months while ALCO worked out the new four-pipe divided low-rise manifold for the GE constant-pressure RD-1 turbocharger.

Thirty-one locomotives built by Alco between February and May 1950 were powered by a 12-cylinder 244C 1,600 horsepower (1,200 kW) engine.

ALCO built the RS-2 to compete with EMD, Fairbanks-Morse, and Baldwin Locomotive Works.

In the case of ALCO, Fairbanks-Morse, and Baldwin, each company increased the power of an existing locomotive line from 1,500 to 1,600 hp (1.1 to 1.2 MW), and added more improvements to create new locomotive lines.

The Delaware and Hudson Railway rebuilt 13 of its RS-2s for passenger service, including on the Laurentian.

Kennecott Copper 103 is at the San Diego Railroad Museum in Campo, California.

The first production RS-2, originally sold to the Detroit & Mackinac RR as their number 466, was fully operable in freight service on the Michigan Southern Railroad (1989) until a few years ago.

The former Elgin Joliet and Eastern 801 is preserved in Jala, Mexico as a Las Encinas SA de CV 801.