This is spot on - it'll be a long time before those battery buses actually roll out. Keep in mind that the T has exactly 5 full BEB's (currently used on the Silver Line, in limited service) and is far behind many other transit authorities in testing BEBs. There are no BEBs on order currently - the most they've committed to is 60' hybrids with "enhanced electric only mode" to allow them to scrap the Silver Line electrification in the tunnel.*
If sanity prevailed at the T, they could have built a new BEB garage somewhere first, and started by assigning BEBs to the routes that currently operate straight diesels (this is in part happening in Quincy), while getting another generation of ETB's (with in-motion charging) to base at North Cambridge. This would have allowed real-world testing of both concepts side-by-side, all while ensuring that bus electrification proceeds with a "dirtiest first" policy. Instead, Lynn and Fellsway garages will continue to run straight diesel buses, while the only fully-electric garage is gutted for a pricey rehab.
The T has tried to kill the North Cambridge routes several times, but it's always been municipal pushback which has stopped it. I suspect they believe (probably rightly so) that there's enough wishful thinking about BEBs that the City of Cambridge will let this slide. Rip out the OHW and distribution system fast, and by the time anyone can object it's impossible to revert. My guess is the line crews will be out the very first day after closure ripping down the wires.
One poster mentioned Mt Auburn St - that's likely a factor. Both the Mt Auburn reconstruction, and a smaller project on the Cambridge portion of Belmont St, have been delayed due to "consultation with the T." I suspect the T is seizing the opportunity of those projects as an excuse to accelerate the ETB retirement, and avoid having to restore the OHW after - which is sad, since as with the Trapelo Road reconstruction, they could have tapped highway funds through MassDOT to rebuild the overhead. Keep in mind that Trapelo Rd/Belmont St, Cambridge line to Waverly, got all-new OHW in 2016 paid for with highway funds - that's all going to get ripped down after only six years of use.
*The Silver Line "Enhanced Hybrids" are even more egregious. In order to satisfy the T's desire to eliminate the Silver Line tunnel OHW, these buses will run diesel engines in East Boston and Chelsea to generate power to use in a tunnel with overhead wire! More local source emissions for Chelsea and East Boston, so the T can save a few maintenance bucks on the tunnel.
Wondering if I'll see the Western Route double-tracking finished before I retire...
Photo: Melbourne W7 No. 1019 on Route 78, Bridge & Church Streets, Richmond, Victoria. 10/21/2010