In her first major announcement as a mayoral hopeful, Sarah Thomson revealed details of her $14-billion plan to expand the city’s subway.

If elected, Thomson says, she would add 58 kilometres of track, expanding the lines west to the airport, east through Scarborough and north to York University. (The last is already in the works.)

To pay for the ambitious project, Thomson said she would implement road tolls for the city’s two highways.

“We could generate between $400 million and $500 million per year on the Gardiner and Don Valley Parkway with a $5 toll,” she told a small group of reporters at a news conference yesterday morning, staged in front of the Wellesley subway station.

The tolls, she continued, would come with a sunset clause of 10 years.

Additional funds would be raised through private partnerships and redirecting funds currently allocated to expand the LRT system.