And they are getting from the esplanade to Hynes, and from Hynes to the D how?
Unless they propose deep-boring beneath the back bay (probably impossible for umpteen reasons), the only way to do it is make a tight 90° turn onto Mass Ave, dig it up, build a super deep station under Mass Ave (has to be underneath the Comm Ave underpass and green line), then make an even tighter 70something° turn onto the Mass Pike/Newbury St/Worcester Line, and go even deeper to get under the Muddy. Then they propose building a station somewhere at yawkey (beneeth the pike?, the existing CR station?) before merging with the existing D.
What.The.Fuck
If riverbank and blue-eats-D is ever going to happen, routing it down the Charlesgate is the ONLY way that makes sense. You still have to build a new station beneath Kenmore because only the inside tracks were designed for heavy rail conversion (and they only feed the B line) and the outside tracks have to be retained as light rail for the C. But that's much less an issue than this insane routing to get to Hynes for no discernible reason other than a connection to the 1.
Some other issues with converting the D to heavy rail:
1) On paper, the grade-separated isolated ROW looks prime for conversion. But it's only grade-separated from roadways. Almost every single D station has HEAVILY utilized at-grade pedestrian crossings that would need to be accommodated. Brookline Village and Eliot are prime examples of this, but almost every station has a pedestrian crossing that gets used for more than just boarding trains. There's also the crossing out by Hammond Pond.
2) Every single station would need to be rebuilt from the ground up. No at-grade crossing of a heavy-rail line means ADA accessible platforms with two elevators minimum. Most of the stations would have to be moved slightly or closed. I have no idea what you'd do with Brookline Village, it would probably have to be buried.
3) Riverside. You're cutting off the main LRV storage and maintenance facility. Sure the blue line uses overhead catenary (the only pro of this idea, you don't have to swap out the power systems) so the LRVs could still access it... outside of service hours. Since the LRVs are wobbly at speed they couldn't co-mingle with the BL fleet without killing their trip times.
4) Reservoir. Not that the T takes advantage of this, but you eliminate the possibility of routing BC trains down the D branch in case of service inturruptions.
5) No D-E connector, and all of the potential benefits that would bring to the system.
6) Service capacity. Does the D even need the capacity of six car heavy rail trains? Newton is just not that dense, and even at rush the trains aren't that full (relatively), and when they are its typically because of delays and not train capacity. Newton's not going to get much denser, so where is the ridership to justify rebuilding every single station, a new GL storage yard/maintenance facility, an expanded BL fleet, and the new tunnel beneath Storrow? This is always my biggest question with a heavy-rail D. Will it ever need more than four car LRV trains? I doubt it.
7) Needham. You just eliminated and/or made replacing CR service to Needham virtually impossible, and at minimum vastly more expensive. There are several crossings that would need to be grade separated, turning the project from a "lay a second track and wires" to "completely rebuild the entire ROW".
This is why I tend to get apprehensive (and a bit upset) when these student ideas, the product of at most 2-3 months of study (because unless it's a thesis its probably only a half-semester project) get a ton of attention in the press when ideas that have been being hashed out for years by people on forums, etc, are ignored. Van's ideas have been out there for ever, and have inspired multiple iterations (several on here) that are vastly superior to this swiss-cheese proposal. And yet the only credit he got was the un-credited thievery of a graphic.
All of the issues of the D getting crowded in the central subway are solved with the D-E connector, and either some version of F-Lines idea to go from Back Bay to the abandoned Pleasant St portal or the Stuart Street subway, which has been proposed for ages. It's probably a lot cheaper than this idea as well. If the riverbank is ever built as an express bypass, it makes a million more sense to send rapid transit capacity where its needed: Allston, Watertown, and eventually Waltham.
