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 "Burlington Northern Railroad"): The Burlington Northern Railroad (reporting mark BN) was a United States-based railroad company formed from a merger of four major U.S. railroads.
Relevant evidence: Yes