So it looks like the Charliemont Metro station is sub-surface, and the connection to the Green line is between Darthmouth Road and Northbrook Road. That gives about 80m to get from tunnel mouth to elevated level. Is that possible?
Also, I wonder how deep the tunnel needs to go under the canal, and how deep the Charlemont station needs to be. I would assume stations on a steep incline aren't permitted.
I see it's now going to be on the East side of Sephen's green. I guess another Green line connection isn't important, but it also could be problematic for an integrated Stephen's Green Station if DART Underground does ever get resurrected.
The one change from Metro North I'm in fovour of is the moving of the Maynooth Line interchange to Whitworth. This creates the possibility of connecting to both surface rail lines.
But I think connecting to the Green line is a mistake. It will create all kinds of operational problems in the long run, and keep the whole line from running at full capacity.
I also think building the underground stations with 60m platforms is rediculously short sighted. You can't just tack on an extra 20m to the platforms the way you can with surface platforms. They need to allow for future expansion from the start and build the platforms at least 100m long.