The St. Louis–San Francisco Railway (reporting mark SLSF), commonly known as the "Frisco", was a railroad that operated in the Midwest and South Central United States from 1876 to November 21, 1980.

At the end of 1970, it operated 4,547 miles (7,318 km) of road on 6,574 miles (10,580 km) of track, not including subsidiaries Quanah, Acme and Pacific Railway and the Alabama, Tennessee and Northern Railroad; that year, it reported 12,795 million ton-miles of revenue freight and no passengers.

This land grant line was one of two railroads (the other being the M-K-T) authorized by the federal government to build across Indian Territory.

The receivers retained the western right of way but divested the ATSF of the St. Louis–San Francisco mileage on the Great Plains.

In 1903, Frisco executives engaged in negotiations to purchase large tracts of land in St. Bernard Parish, Louisiana "up to the Orleans Parish line" as part of plans of "gigantic scope" to further the expansion of the company's rail lines and operations facilities across the state.

As part of this plan, the executives proposed relocation of the residents of the historically Black community of Fazendeville to the much smaller, neighboring village of Versailles, which was described as a "settlement consist[ing] merely of a row of very small properties along a public road running at right angles from the river to the railroad track"; however, many of Fazendeville's residents resisted and then ultimately refused the railway's financial offers.

"[5] In 1901, the Frisco took control of the Fort Worth and Rio Grande Railway, which it operated as an independent subsidiary, and constructed several extensions of the latter.

However, after the Frisco entered bankruptcy in 1913, it made no further extensions of the FW&RG, which in most years failed to make a net profit.

[6] In 1937 the Frisco sold the FW&RG to the Atchison, Topeka and Santa Fe Railway for $1.5 million, giving the latter an entry into Fort Worth from the west.

In 1912 a new facility was built in Memphis, Tennessee to handle the eastern section of the system, consisting of a yard, roundhouse terminal, and car shops.

These included: The core of the former Frisco system continues to be operated by BNSF Railway as high-density mainlines.

[71][72][73] These railway vehicles were commonly known as "Doodlebugs" for their insect-like appearance and the slow speeds at which they would doddle or "doodle" down the tracks.

[70][74] An initial order for ten was placed in 1910, with seven more arriving by 1913, putting Frisco in the forefront of gas-electric operation at that time.

[70] Frisco's peak year for motor-car mileage was 1931, and its fleet at that time included twenty-three gas-electrics, five gas-mechanical cars, four trailer coaches, and six mail-baggage units.

[35] Frisco’s first acquisition of diesel locomotives came in November 1941, when the line received five Baldwin VO-1000 switchers of a 1,000-horsepower (750 kW) each.

The Frisco operated in that part of the country, and supplied construction help to the Park, along with the rails and ties, back when this line was being built in 1962.