The Biotren is an at-grade urban commuter rail system that covers a big part of the city of Concepción, capital of the region of Bío-Bío, also known as Greater Concepción or Concepción Metropolitan Area, both synonyms of "city" according to the urbanistic standards and laws of Chile, of which this city is the second biggest, most populous and important of the country. Biotren connects the boroughs or comunas of Concepción Centro (downtown borough), Talcahuano, Hualpén, San Pedro de la Paz, Chiguayante and Hualqui. The system is managed by Ferrocarriles Suburbanos de Concepción S.A. (Fesub), which name comes from the former metrorail system of the city and is a subsidiary of Empresa de los Ferrocarriles del Estado (EFE), Chilean State Railways. Biotren is part of the Plan and Authority of Integrated Transit of Concepción, Biovías.