There is potential in two locations for tunnelling work. Transportation engineers are due to submit reports on the alignment in December. Currently there are three options for the line to cross the Bow River: by tunnel, building a new bridge, or attaching a bridge to the lower level of an existing bridge. In the downtown, it is undecided whether the alignment will be at grade, elevated or in a tunnel.

Mayor Naheed Nenshi said he wants construction on the north-south line to begin in 2017, with completion by 2024. The project will double the city’s LRT system, adding 40km of track to the existing 59km LRT network. In January 2014, Calgary’s City Council approved funding of CAD 520M (USD 401.5M) for the planning, design and construction of the Green Line.

According to the city, the Green Line was initially planned to be constructed over 30 years’ time, starting as a bus-only Transitway, and later converting to LRT. "This announcement from the Federal Government means that Calgarians in the north and southeast areas of the city will be able to enjoy faster, more reliable, light rail service ahead of schedule."