The City of Calgary will be moving ahead with a route plan for the Green Line that will involve a tunnel under the Bow River and City Centre.

The tunnel, which would run underneath Centre Street, is the most expensive plan put forward by council.

There are no cost estimates on it, but it will cost about $500M more than the other options.

Council had five options to choose from when it came to connecting the north and south ends of the city with the Green Line.

Some included street-level LRT lines while others involved a series of bridges.

Officials say that discussions are still in place over what route the tunnel would take through the Beltline.

Even though it’s an expensive proposal, Ward 12 councillor Shane Keating says Calgary needs to think long term.

“Today is the next phase. We’re looking at what’s best for the City of Calgary. When we look at the core and we look at the way we hear often about the LRTs we have today – ‘why didn’t go underground’? It is the most expensive option but, today is really not about the costs, it’s about what’s best for Calgary. Through public engagement, the tunnel is the best option.”

The Green Line would run 40 km from North Pointe to Seton and it’s estimated that it would serve 41M passengers every year.

There is no information on how much the provincial or federal government would contribute, and there is no firm time line on when shovels could be in the ground.

Officials will now be holding public engagement meetings on the proposal.