the Milwaukee Road and finally the Indiana Rail Road. Variations on trackage rights include "direction running" agreements between two railroads with parallel lines through an area, usually done to facilitate greater traffic volume. For instance, CSX and NS have a directional-running agreement between downtown Cincinnati, Ohio and nearby Hamilton, where northbound trains generally use NS trackage and southbound trains (with the exception of Amtrak's Cardinal) use CSX tracks. North of Hamilton, NS trains use CSX tracks on a traditional trackage-rights agreement for a two-mile (3 km) section. Bibliography See also List of early British railway companies List of railway companies involved in the 1923 grouping Joint station (UK), Union station (USA) References British joint railway companies