Like thousands of 905ers, Andrew Simurda's daily trip to work has given him a window-side view of Greater Toronto's mounting transportation problems.

For the past 15 years, the portfolio manager has eschewed the car in favour of a leisurely 45-minute GO train commute from his home in Richmond Hill to the Union Station terminus and on to his office at Queen and University. In that time, GO has tripled the size of the parking lot at his suburban stop. At the other end of the journey, he says he mostly avoids the PATH network "because the congestion in the tunnels is pretty bad." Those throngs, however, are just the thin edge of the wedge.

Within 15 to 20 years, according to Metrolinx, the number of bodies passing through the 85-year-old Front Street terminal is expected to double or even triple, propelled by the turbo-charged combination of population growth, expanded GO service, and the construction of more downtown office buildings, such as the second Bay Adelaide tower, announced earlier this month.

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This looming squeeze play has Metrolinx casting about for answers. After almost a year of discussions with three consulting teams, the provincial transportation agency is focusing on two possible – and radical – solutions to a central dilemma: should Metrolinx attempt to force millions of additional commuters through an already constrained portal, or if it should seek to disperse the traffic volumes elsewhere in the downtown?

One proposed fix involves digging a GO rail tunnel underneath the existing Lakeshore corridor that would be linked to a new underground platform concourse just to the southeast of Union Station – a configuration similar to New York's Penn Station.

The other option looks at creating a second terminal further west, on the rail corridor near Bathurst or Strachan, and then building a downtown relief subway line that connects this "shoulder station" to the downtown office district, then runs east along Queen Street and ultimately swings up the Bloor-Danforth line around Pape (this DRL would also extend down to the CNE).That new terminus, dubbed the Bathurst North Yard Station, would mainly serve commuters from the north and western regions of the GTA. It could divert as many as a third of GO riders before they reach Union Station, according to the agency's preliminary estimates. Given the growth projections, that could mean more than 200,000 riders per day. This option could drastically alter the future growth of the downtown by re-directing office development westward. In fact, any major changes to Union Station – the focal point of the GTA's rapid transit network – will have a ripple effect. "We need to understand the impact on the entire system," says Leslie Woo, the agency's senior planner.

Metrolinx has yet to reveal details about the expected cost (large), the planning and construction timelines (lengthy), the funding strategy (uncertain), the implications for its other expansion projects (complicated), or its preference among the two options (under review). The agency has promised to release a long-term investment strategy next year, and Ms. Woo says officials will be in a better position to offer cost estimates by then. Suggestions for funding sources include road tolls, parking levies, and a Los Angeles-style regional sales tax.

Even at its current volume, Union Station is by far Canada's busiest transportation hub. Approximately 250,000 people use the Front Street station each weekday, and the entire train, subway and bus system operating within the station precinct handles upwards of 65 million riders per year. Lester B. Pearson International Airport, by comparison, handles half that volume.

If Metrolinx's projections bear out, the tsunami of commuters flowing from GO trains, as well as the overtaxed Yonge-University-Spadina subway line, will eventually congeal into a massive blockage, even with the $1.1-billion GO concourse expansion currently underway and a $90-million project to widen the platform at the Union Station subway stop.

"There's only so many tracks, and you can only get so many trains in and out of there," says former chief planner Paul Bedford. And, he warns, 2031 (Metrolinx's current planning horizon) "is not that far away."

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To put the date into perspective, construction on the Air Canada Centre, which re-oriented the Union Station precinct towards the railway lands, started 15 years ago. The TTC's subway platform project has been in the works for a decade.

Ms. Woo says that over the next 10 years, Metrolinx will double the station's capacity with the introduction of faster trains and other logistical changes. Transit experts also predict that future TTC expansion – new LRTs on Eglinton, Sheppard and Finch – will pour even more traffic into Union Station.

The longer they wait to make a decision, the fewer choices they may have. Rapid growth south of the tracks may soon eliminate the option of a second, underground concourse, as ongoing high-rise development could block possible entrances and exits.

But transit experts are concerned about an even more fundamental problem associated with attempts to enlarge Union Station: "In general, the more you focus on one point, [the more] you're creating congestion and new problems for yourself," observes University of Toronto professor of civil engineering Eric Miller, a transit expert who headed the panel that recommended the LRTs to city council earlier this spring.

Mr. Bedford points out that most large city-regions have multiple train stations, which serve to spread out the load and link different types of transit services. Toronto, in fact, used to have many smaller suburban train stations, as well as the Summerhill station, now an LCBO outlet. But the railways decommissioned these stops in the post-war period as car ownership replaced the train as the preferred mode of travel.

"Some degree of decentralization has to happen," adds Roger Keil, director of York University's CITY Institute, citing large European transportation hubs that link local, regional and inter-city transit service to airports and central business districts. "You can't just try to solve one problem at a time."

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Ms. Woo stresses that Metrolinx will only build a new station where demand warrants, which means anticipating the changing shape of the downtown core. In recent years, new office buildings have sprung up in the so-called "south core," near the ACC (more, such as an 800,000 square-foot tower proposed by Cadillac Fairview, are on the way. And since the late 1990s, commercial developers have converted millions of square feet of brick warehouses between Spadina and Liberty Village – an area that a second, more westerly terminal, would serve directly.

Yet Iain Dobson, a real estate consultant who studies the office market for the Canadian Urban Institute, points out that the supply of convertible warehouses is finite. "At some point," he says, "we've got to build more office space downtown or those jobs will go someplace else."

A possible shoulder station around Bathurst, linked to a new subway into the core, will almost certainly attract the attention of commercial builders, large corporate tenants and speculators, even if these dramatic infrastructure options are, for the time being, no more than lines and circles in a report to the Metrolinx board.

But Mr. Bedford wants Metrolinx officials to put the pedal to the metal so they can have solutions at hand before Union Station begins to seize. "You've got to think ahead," he urges. "This stuff doesn't fall from the sky, and it isn't free."

Special to The Globe and Mail