History of Toronto
In 1998, the six municipalities comprising Metropolitan Toronto – East York, Etobicoke, North York, Scarborough, York, and the old City of Toronto – and its regional government were amalgamated into a single City of Toronto (colloquially dubbed the "megacity") by an act of the Government of Ontario. This was despite a municipal referendum in 1997 that was overwhelmingly against amalgamation. Subsequently, Mel Lastman defeated Barbara Hall to become the first elected mayor of the megacity.
Toronto and Mimico Electric Railway and Light Company
On August 16, 1922, the City of Toronto formally acquired the T&YRR lines. The plan was that the city portions of the T&YRR radial lines would be incorporated into the TTC, and the portions outside the city would be managed by Ontario Hydro as the Hydro-Electric Railways: Toronto and York Division. 
On November 1, 1922, Hydro-Electric Railways took over operation of the T&YRR lines outside of the city limits. The TTC replaced the radial line between Sunnyside and the Humber River with a double-track streetcar line. After 1922, Hydro changed the gauge of the Mimico line between Humber (the line's new eastern terminal) and Port Credit from Toronto gauge to standard gauge. HER introduced new standard-gauge cars and doubled service frequency.