The TTC has expanded its free Internet service to include four more Toronto subway stations.

Wi-Fi is now available at Sherbourne, Bathurst, Christie and Castle Frank Stations, the TTC said in a statement Friday.

Service was already offered at Union, King, Queen, Dundas, St. George, Bay, Bloor-Yonge, Wellesley, College, St. Andrew, Osgoode, St. Patrick, Queen's Park, Museum and Spadina Stations.

The TTC has been rolling out free Wi-Fi since 2013, and all stations are expected to have Internet service by early 2017. Stations will also be outfitted to provide cellular service.