Alton Route historically had numbered subdivisions, which were retained after the 1947 acquisition by Gulf Mobile & Ohio. The old Gulf Mobile & Ohio used named districts. In 1972, Gulf Mobile & Ohio merged with Illinois Central forming the Illinois Central Gulf Railroad. And Illinois Central's use of named districts was adopted. In 1987, these lines were sold to the newly formed Chicago Missouri & Western Railway. Which quickly went bankrupt, and in 1989 the lines were sold to Gateway Western Railway. In 1997, Gateway Western was acquired by Kansas City Southern, which uses named subdivisions.