In 1910, Southern Motor Works built additional premises named the Marathon Motor Works in Nashville to produce the Marathon automobile.

[2] The Marathon motor, a four-cylinder engine in unit with a transmission, was designed by William H. Collier of Southern Motor Works.

By 1913, the Marathon was available in three different chassis sizes and at least 10 different body styles.

The three chassis sizes were:[3] In 1914 Marathon prices were mid-range from $975 to $1,470,(equivalent to $44,715 in 2023)[3] The Marathon was popular with the public, and by 1912 was producing 200 cars monthly.

[1] [3] H. H. Brooks, General Sales Manager, arranged for an Indianapolis automaker to take over sales of the Marathon in 1913 while the company was having financial difficulties.