It is the Empire Coal Mine & Railroad Co. located at Antioch, CA. It ran from the Wharf at Antioch south to the Coal mines at Stewartsville from 1878 to 1897, 3 ft. gauge. It was one of California's more obscure ng operations. The mine sites are located in the Black Diamond Mines Regional Preserve south of Antioch. WESTERN RAILROADER issue 370 has the story of all three coal mine railroads in the area.