sentences:  Branded under the Merseyrail name, the routes are operated by Northern Trains on behalf of Merseytravel.Unlike the Merseyrail network, which is a partially underground rapid transit/commuter rail system with largely isolated infrastructure, the City Line serves a larger area using main line routes shared with regional, national, and high-speed services.The City Line can trace its origins back to the dawn of the railway era, as it incorporates most of the route of the Liverpool and Manchester Railway, opened in 1830 and including Broad Green Station, the oldest operating station in the world.