Chicago, Indianapolis & Louisville Railroad

Monon Railroad

A postcard depiction of the Thoroughbred, with an EMD F3 in the lead.
Reporting mark	CIL, MON
Locale	Illinois, Indiana, and Kentucky
Dates of operation	1847 (1847)–1971 (1971)
Successor	Louisville and Nashville
Track gauge	4 ft 8 1⁄2 in (1,435 mm)
Headquarters	Chicago, Illinois

The Monon Railroad (reporting mark MON), also known as the Chicago, Indianapolis, and Louisville Railway (reporting mark CIL) from 1897 to 1956, was an American railroad that operated almost entirely within the state of Indiana. The Monon was merged into the Louisville and Nashville Railroad in 1971, and much of the former Monon right of way is owned today by CSX Transportation. In 1970 it operated 540 miles (870 km) of road on 792 miles (1,275 km) of track; that year it reported 1320 million ton-miles of revenue freight and zero passenger-miles. (It showed zero miles of double track, the longest such Class I railroad in the country.)

The Monon served six colleges and universities along its line:

The university traffic was important enough to the Monon that the railroad used the schools' colors on its rolling stock. The red and white of Wabash College (and similar to the colors of Indiana University) was used on the railroad's passenger equipment, and the black and gold used by both DePauw University and Purdue University adorned the railroad's diesel freight locomotives and later replaced the red and white on passenger equipment as well.

The railroad got the name Monon from the convergence of its main routes in Monon, Indiana. From Monon, the mainlines reached out to Chicago, Louisville, Indianapolis, and Michigan City, Indiana. In Chicago the Monon's passenger trains served Dearborn Station. Branches connected the Louisville mainline to Victoria, Indiana and French Lick, Indiana.