sentences:  By 1918 Muni was in direct competition with the United Railroads of San Francisco (the successor company to the Market Street RailRoad Company) down the length of Market Street; the two operators each operated their own pair of rail tracks down that thoroughfare, which came to be known as the 'roar of the four'.The two Union Railroad tracks were on the inside and the two San Francisco Municipal Railway tracks were on the outside.In 1892 The Owl Drug Company was established at 1128 Market Street and later grew into a leading American drugstore retailer.