The Rock Island Southern Railway, or RIS, was one of the most unusual interurban systems in the United States.
This division operated on 600 volts DC electric power and used typical interurban standards, with tighter curves and narrower rolling stock than in use on mainline railroads.
Passenger service was operated for two decades, ceasing in 1926 following a decline in ridership brought on by increased automobile use.
The long cuts, fills and high trestles that the line used to traverse the hilly Mississippi Valley country south of Rock Island were notable features of this division.
This slow death culminated in the last run of a RIS steam engine in Rock Island in February 1952.