TORONTO -- The federal Liberals are earmarking $1.8 billion in idle, Conservative infrastructure cash to a regional express rail project around Canada's largest city and millions more for smaller transit projects around Ontario.

Combined with provincial money, the federal and provincial governments are pitching in $4.4 billion to GO Transit's regional express project that will add track and parking capacity and renovate stations in and around Toronto.

The price tag for the project makes it the largest project the federal government has ever invested in, Prime Minister Justin Trudeau said at an event in Etobicoke.

Trudeau predicted that once completed, the public spending will make for a faster commute around the Toronto region and "more money in peoples' pockets as they trade their cars for public transit."

The federal dollars will come from the marquee infrastructure program set up by the previous Conservative government that the Liberals are now pushing provinces to start allocating to projects -- or else watch the billions remaining in the New Building Canada Fund flow directly to cities.

An additional $200 million announced today comes from the first phase of the Liberals' infrastructure program that started last year, which will fund 312 transit projects in 28 Ontario cities.

The Liberals plan to spend $82.8 billion from their infrastructure program over the next decade, not including the approximately $100 billion to be spent over the same time from previous infrastructure programs.

The Liberals are banking that the investment will boost economic growth rates.

Finance Minister Bill Morneau's second budget laid out a few more details of the how the government plans to spend the infrastructure cash during the second phase of the program, but the precise spending rules won't be unveiled until the Liberals finalize funding agreements with provinces over the next year.

The budget also eliminated a tax credit for transit passes, much to the chagrin of riders who will no longer be able to write off part of their cost.

Trudeau said the "boutique tax credit" didn't increase transit ridership, which it was supposed to do.

"The numbers do not bear out that more people took public transit because of this tax credit and on top of that it does absolutely nothing for low-income Canadians ... who rely to a greater proportion on transit," he said.

PM Trudeau tweeted: