It formed an important link in the through route of the Southern Pacific Company between New Orleans and San Francisco.

The principal branch lines extended from Lafayette to the Mississippi River opposite Baton Rouge, from Lafayette to Cheneyville, from Breaux Bridge to Port Barre, from Breaux Bridge to Cade, and from Thibodaux Junction to Napoleonville.

[3] By early 1861, track was laid for 80 miles (130 km) west of Beaumont and the trackage to Houston was complete.

In spring 1862, the President of the Railway, Abram M. Gentry, stated that the 110-mile (180 km) line from Houston to Orange was open, but some of the track was temporary for military needs due to the Civil War.

The Trinity River Bridge washed out in 1867 and the Texas and New Orleans continued to offer service between Houston and Beaumont until spring 1868, at which time the company was forced into receivership.

In the early years of the 20th century The Texas and New Orleans built over 160 miles (260 km) of track, much of it between Cedar and Rockland, opening up a through route from Dallas to Beaumont.

At the end of 1925, T&NO operated 545 miles of railroad; to simplify SP's corporate holdings T&NO leased the other Texas-Louisiana SP lines in 1927, including: In 1934, all of these were merged into T&NO, making it the largest Texas railroad with 3,713 miles (5,975 km) of road (not all in Texas).