Transport Canada is expected to approve or deny Via Rail's multi-billion-dollar proposal to flesh out a new rail line between Toronto, Ottawa, Montreal and Quebec City by the end of the year.

A few years ago, Via Rail unveiled a $4-billion plan to increase service on the busy corridor not by letting trains go faster, but by building up a new passenger train line to the north of its current line, which it shares with freight trains.

"In southern Ontario, the current rail system along [Lake Ontario] travels in a high-traffic area, so the service has become unreliable and Via hasn't been able to expand service," said the University of Toronto's Matti Siemiatycki in an interview Monday on CBC Radio's Ontario Morning.

The federal government set aside $8 million in its 2018 budget to study the idea sometime between then and 2021, saying it would figure out its potential ridership and cost.

In an emailed statement Monday, Via Rail said it expects the government to finish its proposal and make its decision this year.

If approved, the new line would use Via Rail's new Siemens trains, which Via said would be bought at a pre-set price of up to $575 million under the deal signed last month.

A Transport Canada spokesperson said in an email it's "taking the time necessary to determine the best approach to delivering a safe, efficient and reliable intercity passenger rail service in Canada," without making the same end-of-year commitment.

Public partially in dark

The line would re-establish the train link between Toronto and Peterborough, Ont., that was cancelled in the 1990s.

Siemiatycki, an associate professor of geography and planning, said the information available doesn't let the public decide if any tax dollars invested to build tracks would be worth it.

"It's not clear the number of riders this new line would attract would outweigh the heavy costs," he said.

"We need to see the [government] studies, they cost millions of dollars. They need to be released publicly so the debate isn't based on dreams but really based on technical evidence and weighed against other alternatives."

The money could potentially be better spent expanding local public transportation in these communities or being dedicated to the regional GO Transit network in the Toronto area, he said.