The Toronto subway an RT is the main rapid transit (RT) railway system in Toronto, Ontario, Canada operated by the Toronto Transit Commission (TTC). Since the original line following Yonge Street opened in 1954 with 12 stations, the network has expanded to become Canada's largest rapid transit rail network, encompassing four lines and 69 stations on 68.3 kilometres (42.4 mi) of track. The subway system is a very popular mode of public transport in Toronto and the largest in Canada in terms of passenger usage, with an average of 1,211,300 passenger trips each weekday (as of 2006-2007).