It is one of many plans discussed by Toronto and the province over the last seven years. In fact, so many plans have emerged it's difficult to keep track.
The first major plan came in 2007, when then-mayor David Miller introduced Transit City, an eight-line expansion using light-rail transit. By 2009, the provincial government promised $7.2-billion to a scaled back version of the Transit City plan, with two lines going into Scarborough. The federal government, along with the province, would later pledge $950-million for a light-rail line along Sheppard Avenue East.
Then Rob Ford became mayor.
Ford cancelled Transit City and promised subways, saying that some of the funding for the subways would be coming from the private sector.
Coun. Karen Stintz, the chair of the TTC, in the meantime, developed a plan called OneCity, which also relied on light rail transit.
Above is a map of only three of the proposals, focusing on Scarborough.