The Burlington Northern Railroad (reporting mark BN) was a United States-based railroad company formed from a merger of four major U.S. railroads. Burlington Northern operated between 1970 and 1996. Its historical lineage begins in the earliest days of railroading with the chartering in 1848 of the Chicago and Aurora Railroad, a direct ancestor line of the Chicago, Burlington and Quincy Railroad, which lends Burlington to the names of various merger-produced successors.