In reading more on the Green Line, you really have to go to every possible source to get the full picture... In this article there was an interesting quote from Chabot.
Ward 10 Coun. Andre Chabot noted a need to advance the project forward, adding that while the province has said it won't support a Green Line alignment that includes tunnelling, the city and province could explore other options aside from the elevated tracks.
"I'm hoping through this assessment of the downtown core that we can come up with a solution that all Calgarians, including downtown businesses, can live with," Chabot said.
Is Chabot saying maybe a small underpass (don't call it a tunnel) and/or (at least partial) surface line is STILL on the table? If we're talking everything but tunnelling, that is how I read it. They know they need to get from Grand Central to 7th Ave, I think how they get there is still up for study/debate.