Green Line tunnel option approved in principle by Calgary city council

Calgary city council voted Tuesday in favour of what's seen as the best but most expensive option for the eventual new Green Line of the LRT — a $2-billion tunnel beneath Crescent Heights, the Bow River and downtown.

Councillors see underground route from north-central Calgary to Beltline as best, but worry about $2B cost

A rendering of what the underground station at Centre Street and Ninth Avenue North would look like if Calgary goes with a tunnel for the route of the new Green Line of the LRT system. (City of Calgary/Screenshot)

Calgary city council voted Tuesday in favour of what's seen as the best but most expensive option for the eventual new Green Line of the LRT — a $2-billion tunnel beneath Crescent Heights, the Bow River and downtown.

But, hedging slightly, councillors were careful to add a two-word caveat — "in principle" — to their recommendation to city staff to pursue the tunnel option, which was one of several proposed to get the future light-rail line from a point north of 16th Avenue North all the way to 10th Avenue South.

Coun. Peter Demong, in particular, worried about the price tag of the tunnel and whether it would break the still-uncertain budget for the megaproject.

"The underground option is, more than likely and from everything I've read, the best option," he said.

"But just because it's the best option, if we can't afford it, when we look at the entire line or at least a good portion of line in its entirety, what's the point of making something, if you can't make it a usable option?"

The federal government has committed $1.5 billion to the Green Line, which is to run all the way from the city's northern periphery to the deep southeast community of Seton, and the city has earmarked $1.5 billion of its own to be accrued over a period of 30 years.

The planned route of the Green Line is indicated by the green line on this map. (City of Calgary)

But the Alberta government has yet to make a formal commitment to the project and, even if the province kicks in matching funds, councillors expressed worries that the combined $4.5 billion will fall well short of what's needed to build the entire Green Line.

Coun. Shane Keating acknowledged that major funding questions remain, but said that shouldn't stop the city from pursuing the tunnel as a serious and leading choice for the north-central section.

"Let's build the strongest possible skeleton for the future development of the Green Line," he said. "As the funding picture becomes clearer, we can decide on how this project will take shape."

At an estimated $1.95 billion, the tunnel was more expensive than four other options being considered for the north-central stretch of the Green Line, which ranged from $1.5 to $1.8 billion.

All those price tags are "Class 3" estimates, meaning they are believed to be accurate in a range of -30 per cent to +50 per cent.

The full-tunnel route would see the LRT line run underground from a point north of 16th Avenue North all the way south to the Beltline in a tunnel beneath both the Bow River and downtown Calgary. (City of Calgary/Screenshot)

Other options for crossing the Bow River included running the LRT line down the existing Centre Street Bridge and building a new bridge that would run over Prince's Island Park into Eau Claire.

To get through downtown, meanwhile, the other options included a shorter tunnel beginning at Eau Claire and an elevated LRT line that would run from Eau Claire down Second Street S.W., over top of +15 walkways along the way.

A consultant's report suggested the elevated platform would hurt property values along Second Street, however, and cost the city an estimated $680 million in lost property taxes over 30 years.

For the section of the Green Line that would run through the Beltline south of downtown, council also voted Tuesday to instruct city staff to continue investigating an underground tunnel beneath 12th Avenue South as an option for moving trains to the east and connecting to the eventual southeast leg of the line.

That option had initially been ruled out by city staff but numerous area residents said they wanted it back on the table.


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