Question: The St. Louis, San Francisco and Texas Railway (SLSF), was a subsidiary railway to the St. Louis-San Francisco Railway, in 1980 it merged into which United States-based railroad company formed from a merger of four major U.S. railroads?
Sentence (from "St. Louis, San Francisco and Texas Railway"): It merged into SLSF at the beginning of 1964; SLSF merged into the Burlington Northern Railroad in 1980.
Relevant evidence: Yes