Edinburgh's main shopping street was originally entirely residential. Lined with houses on just one side, it demarcated the new town to the south. It was with the arrival of the railway (1845-46) that Princes Street started to develop, as department stores and hotels moved in. It has not lost its vocation and its shops draw in the crowds. Most bus routes on the local network pass here, as does the tram line that connects the city centre to the airport.