Route of the Rockets By Brian Schmidt | May 17, 2021 | Last updated on August 8, 2025 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates Route of the Rockets The 1,600-hp Alco RS3 was an all-time best-selling road switcher with more than 1,200 built from 1949 to 1956. Rock Island No. 492, built in 1951, operated in Chicago area commuter service. Rock Island photo Share this article Print Facebook