A TTC study on the potential for a new “downtown relief” subway line paints a near-apocalyptic vision of commuting to Toronto’s core by 2031 — if transit officials don’t come up with a relief valve.

The level of overcrowding, with demand up by a projected 50 per cent, will dwarf today’s discomfort on the Yonge subway.

Existing plans to increase GO and TTC capacity won’t be enough to stem the overflow of commuters trying to get into the downtown core every day, according to the report that goes before the TTC board on Wednesday.

By then, the population living south of College St. between Bathurst and Parliament will nearly double. Employment is projected to grow 28 per cent, and demand for transit downtown will jump to 236,000 trips in the morning peak, from 155,000 now.

“The most serious capacity issues are related to long- and medium-distance trips from the east and north,” says the Downtown Rapid Transit Expansion Study.

Crowding on the Yonge-University-Spadina subway line, which carries about 30,000 people an hour in the morning rush, will be further exacerbated by riders boarding at new stations on the Spadina subway extension into York Region, set to open in 2016.

A second phase of the study will look at what route and stations the relief line would use. But maps in the report suggest a DRL running south from Pape, west along King St. to St. Andrew Station. A second phase would continue west to about Roncesvalles and head north connecting to the Bloor subway. The first phase would cost about $3.2 billion, the western extension, an additional $3 billion.

Related: TTC breaks another ridership record

The roughly sketched route, to cost a projected $6.2 billion, could be extended farther northeast from Pape to Eglinton, carrying commuters from Thorncliffe Park and Flemingdon Park.

The concept for the route has been around for about a century and surfaced periodically, but the space crunch on Yonge and capacity issues at Union Station have brought new urgency to the matter.

Even the new subway trains, which carry 10 per cent more riders, and an automatic signaling system that will make it possible to run more frequent trains on the Yonge line, won’t be enough to handle the traffic of a regional population expected to grow by 2.6 million by 2031.

But there are competing priorities. Councillor James Pasternak (Ward 10, York Centre) thinks an east-west relief line connecting Yonge and Sheppard to Downsview Station is just as important but doesn’t have the same political weight.

That project is also the most likely to be ready to roll in 2015, when the tunneling machines have finished digging the Spadina extension, said Pasternak, because it has already been studied extensively.

“There is absolutely no subway east-west corridor north of Bloor. The way to take the pressure off the Yonge north line and the Spadina-University line is really to drive the boring equipment from Downsview (station) to Yonge and Sheppard,” he said.

The report notes that building new rapid transit lines parallel to the Lakeshore East and West GO lines, with tunneled portions through the downtown, would also help relieve congestion.

Although it’s possible the DRL could move higher in the priorities of Metrolinx’s 25-year regional transportation plan, the first concern is coming up with a transit investment strategy, said Leslie Woo, Metrolinx vice-president of policy, planning and innovation.

“In order to advance any new unfunded projects we need to figure out how we’re going to pay for it … . There’s a lot that needs to get done and a lot is unfunded,” Woo said.

Any decision about the DRL must be based on hard evidence and extensive study, she said.

The $2.28 million TTC study was approved by Toronto City Council in January, to understand the impact of a potential extension of the Yonge subway into Richmond Hill. The TTC approved a second, $1 million phase last month.

ALSO ON THE STAR:

Hudak says he’d try to divert Ontario’s current transit funding to subways

Citizens ready to get real on transit

Loading... Loading... Loading... Loading... Loading... Loading...

More on the TTC

Read more about: