Toledo, Cincinnati and St. Louis Railroad

System map as of 1884

The Toledo, Cincinnati and St. Louis Railroad (TC&StL) was a 3 ft (914 mm) narrow gauge railroad based in Ohio. It began as a subsidiary of the 3 ft (914 mm) narrow gauge Toledo, Delphos and Burlington Railroad (TD&B), which was opened on July 4, 1875, but in 1882 the two companies merged and retained the TC&StL name, which was more descriptive of its extent.

Toledo, Delphos and Burlington Railroad itself originally came about from a merger of several other railroads, including the 4 ft 10 in (1,473 mm) Ohio gauge Iron Railroad founded on February 2, 1848, based in Ironton, Ohio. In 1881, the TD&B reached an agreement with the Iron Railroad to dual gauge a segment of its line by laying its own 3 ft (914 mm) narrow gauge track in-between the Iron Railroad's track. Both railroads merged later that same year, retaining the TD&B name.

The financially troubled Toledo, Cincinnati and St. Louis Railroad system eventually entered receivership in 1883 and was split at foreclosure in 1884 and 1885 as follows:

• Cincinnati Division, built by the TD&B: Dayton, Lebanon and Cincinnati Railroad
• Cincinnati Northern Division, ex-Cincinnati Northern Railway: Cincinnati, Lebanon and Northern Railway
• Dayton Division, completed by the TD&B: Dayton and Toledo Railroad
• Iron Division, ex-Iron Railroad: Iron Railway (converted to 4 ft 8 ¹⁄₂ in (1,435 mm) standard gauge in 1887)
• St. Louis and Toledo Divisions (split at Kokomo), completed by the TC&StL: Toledo, St. Louis and Kansas City Railroad
• Southeastern Division, ex-Dayton and South Eastern Railroad: Dayton and Ironton Railroad