Bloor will need an expensive redo, including more platforms, to handle rush from 905.
Visions of pushing the Yonge subway line into York Region have always fallen apart once officials considered the results of adding thousands more riders to an already overcrowded line.
Nevertheless, this week, city council is expected to give its blessing to the province's planned extension, but not before compiling a list of preconditions in hopes of averting chaos.
The fact is, record ridership is already straining the Yonge line's capacity, setting in motion a vicious cycle of overcrowded trains, longer loading times and more delays. In a daily rush-hour ritual, TTC riders have to let two or three trains go by because those onboard are packed in like sardines.
Metrolinx, the provincial transit authority, predicts that if the Yonge extension is built, the current line will be 40 per cent over capacity by 2031. That's even if GO manages to divert most 905 riders by offering frequent all-day service.
The biggest challenge is Bloor/Yonge station, where crowding causes loading delays.
The TTC is studying the feasibility of adding a centre platform at the Bloor level and two side platforms below at Yonge. This would mean our busiest station becomes a construction zone.
If some of the fixes aren't practicable, the TTC has a plan B: extending the Sheppard subway west to Downsview so Yonge riders can transfer to the Spadina line to avoid congestion.
According to transit advocate Steve Munro, "The TTC is playing a dangerous game with capacity of the subway system."
Munro says the TTC should first be pushing a Downtown Relief Line, or DRL, a proposed rapid transit line travelling roughly from Dundas West Station southeast to Union Station and then northeast to Pape.
But the TTC only has that line in its sights as a last resort, even though a DRL would divert 41 per cent of the riders from crowded sections of the Yonge line.
TTC chair Adam Giambrone says Transit City is the first priority, and the DRL might be examined in 2018.
At roughly a couple of billion dollars, depending on technology and routing, the DRL would be expensive, but it would bring attractive service to large swaths of east and north Toronto.
Metrolinx estimates that the DRL would carry twice as many riders as the Yonge extension, but doesn't foresee building it before 2020, if ever. The priority is regional lines - i.e., those that connect to the 905.
TTC vice-chair Joe Mihevc, who supports the DRL, says that if Toronto must make a deal for the Yonge extension, we need to be very careful what we get in return.
"Is this the best use of $2.4 billion and the $1, $2 or $3 billion on top of that? There are many, many risks.''
Riding the line
Current capacity of Yonge line south of Wellesley at peak times 30,000 riders
Number of riders at peak times if the Yonge line is extended into the 905 42,000 riders (by 2031)
This assumes frequent GO bus service every 10 minutes to divert riders from the Yonge line.
What Toronto is proposing in order to accommodate increased ridership
New, higher capacity subway cars by 2011.
Automatic train control to boost speed and frequency by 2017.
Adding a seventh car to trains.
A second exit at certain stations.
Bloor/Yonge station may have to be rebuilt to deal with overflow crowds.
The costs and timing are unknowns.