A metro station or subway station is a railway station for a rapid transit system, often known by names such as "metro", "underground" and "subway". It is often underground or elevated. At crossings of metro lines, they are multi-level. At street level the logo of the metro company marks the entrance of the station, along with the schematics of the services at the station. Often there are several entrances for one station, saving one from having to cross the street.