Murray told CBC News in an interview the move would be an "economic game changer." He offered few specifics, not even the cost, just that details would be coming soon.
His comments come after Premier Kathleen Wynne announced a $29-billion plan on Monday to build new transit and transportation infrastructure in the province over the next decade. Many of the details of that plan are due to be spelled out in a budget that is expected to be tabled within a month's time.
"One of the priorities is to build a high-speed rail [link] from downtown Toronto, Pearson [International Airport], Kitchener to London," said Murray.
"Many of the mayors of the communities and businesses along the 401 have been asking for two-way all-day service along that line. This has been something we've been working on for a long time."
The new commitment comes after the Liberals pledged to implement all-day two-way GO train service between Kitchener and Toronto. It has also committed to doubling train frequencies in the morning and evening between the two cities and shortening the travel time.
2 dedicated funds for transportation
Wynne said Monday she would divide $29 billion into two dedicated funds: $15 billion to build public transit in the Toronto-Hamilton area and $14 billion for transportation infrastructure – including roads and bridges – in the rest of the province.
Instead of hiking fuel taxes, Wynne said she would detour the provincial portion of the gas tax – about $1.2 billion annually – to the two funds rather than the main government coffers.
Municipalities would still get the two cents per litre – about $320 million – they currently receive for transit projects, she said.
Some of the money will come from re-routing about $1.3 billion a year in gas taxes, Wynne said. The remainder will be raised through debt, including so-called green bonds, and new "revenue tools" that will be kept under wraps until the budget is tabled.
Ontario's portion of the HST that's collected on gas taxes, which amounts to about $130 million a year, would also be re-directed to the funds, she said.
The fiscal plan could make or break the minority Liberals, who need at least one of the opposition parties to support it if they want to avoid an election.
"We need a partner to put our plan in place," Wynne said in a lunch speech to the Toronto Regional Board of Trade.
"That partner could be the Progressive Conservatives, it could be the NDP or if necessary, the voting public."