According to Texas lore, John Higginson, owner of the Memphis, El Paso & Pacific Railroad, maintained regular service between two cities 40 miles apart with no engine (thank you Steve!)

He had committed to serve the route between Marshall, Texas, and Shreveport, La., but the Civil War had reduced his stock to three boxcars.

 He maintained regular service between two cities by loading a team of oxen into the first boxcar; freight and passengers into the second car; and the train’s crew and management into the third car. 

At Marshall, Higginson would start the train coasting down a long descending grade, and at the bottom they’d unload the oxen, hitch them to the front of the train, and drive them until they reached the top of the next hill. Then they’d load the oxen into the first car again and ride down the hill. 

At Shreveport they’d turn around and use the same method to get home.

In The Humor and Drama of Early Texas (2002), George U. Hubbard writes, “With gravity for the downgrades and oxen for the level areas and the upgrades, the little railroad managed to operate in both directions on a timely and consistent schedule.” With no competition on the Marshall-Shreveport line, Higginson (supposedly) maintained a profitable railroad with no engine at all.

Hubbard cites B.A. Botkin’s A Treasury of Railroad Folklore, from 1953. I find that the Southwestern Historical Quarterly ran an item giving essentially the same details in the early 1950s, citing a Texas newspaper of 1918, and Railway World mentioned it in 1911, quoting the Fort Worth Record (which calls it an “old railroad story”). 

https://www.futilitycloset.com/2022/07/23/the-oxen-railroad/

Steve found that 26 newspapers reported the attached story word-for-word between February 1, 1918 and August 16, 1918 - then another one repeated on February 10, 1919, and a last one on February 05, 1920.

https://www.ttarchive.com/Library/Articles/Texas-Pacific_Oxteams-to-Eagles.html

Chapter One: DREAMS OF EMPIRE

Swanson's Landing on Caddo Lake was astir with excitement. Crowded into the tiny lake port that day late in January of 1858 were all the settlers from miles around. By ox cart, horseback, boat and on foot, these hardy pioneers of East Texas had gathered to give the first train of an ambitious little railroad a rousing send-off. Twenty-three miles of track through the pine forest connected Swanson's Landing with Marshall, Texas.

One stipulation of the charter under which the railroad was organized was that service over the line had to begin by February 1, 1858. During the latter part of 1857 the roadbed and track-laying had been completed. But with the deadline only a few days away, the river boat bringing the locomotive still had not arrived.

 Gloom hung heavy over the offices of the railroad until one of the officials discovered something in the charter that solved their immediate problem. The charter, while being very specific about the date service had to begin, did not stipulate the type of motive power to be used. 

This left the way open for one of the most unique freight trains ever to roll over American railroad tracks. 

Amid shouts of encouragement and best wishes, and a liberal portion of good-natured joking, the engineer of the first train hitched three yoke of oxen to the two box cars and one flat standing on the tracks.

 He cracked his great bull whip over the heads of the lumbering oxen and the historical journey was under way. On level ground and up the grades the oxen pulled the three cars. But when the top of a grade was reached the oxen were unhitched, loaded on the flat car, and then oxen and cars sped down the incline with only gravity and simple hand brakes to control the speeding "train."

Then there's this from http://wiki.wcaleb.rice.edu/Southern%20Pacific%20Railroad%20Company#fnref2

Southern Pacific Railroad Company

Originally called the Texas Western Railroad, the Southern Pacific Railroad was unrelated to the later, better known Southern Pacific.

Planters in Harrison County helped to sponsor the construction of the railroad, which by 1858 connected Marshall to Swanson’s Landing on Caddo Lake. At that time it was only 25 miles long, but it “greatly aided planters east of Marshall.”

Part of the construction on the line was done during the Civil War, according to HOT:

During 1857 the railroad constructed twenty-three miles of track between Marshall and Swanson’s Landing on Caddo Lake. During the Civil War part of the line to Caddo Lake was taken up, and the rails were relaid to Waskom where connection was made with the Vicksburg, Shreveport and Texas Railway Company, thus forming a line between Marshall and Shreveport, Louisiana. In 1869 the company completed an additional twenty-three miles from Marshall to Longview. The Southern Pacific was sold to the Texas Pacific Railroad Company on March 21, 1872.

Jeptha Fowlkes was president of the company in 1857 and 1858, when a group of trustees apparently tried to sell the road but were stopped by a judge’s injunction.

from the Lake Geneva Herald, 1918, feb 1st