an electric railway operating below the surface of the ground (usually in a city)
"in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'" an underground tunnel or passage enabling pedestrians to cross a road or railway
Subway Navigator
Maps and stations of subways and other heavy rail transit systems throughout the world, and a route finder detailing the path between any two stations. http://www.subwaynavigator.com/
