(This post was going to have maps, but I figure everyone can use their imagination well enough.)
The year is 2099.
The General Manager of the MBTA is now a Cabinet-level position, reporting directly to the President of the United States, and you have just received an urgent page to report to the Oval Office. You enter and she immediately gets down to business. "The Green Line must be converted to Blue Line-style heavy rail immediately. This is a matter of national security."
"National security, Madam President?" you repeat in disbelief.
She nods. "National security." The gears in your head start turning.
"We should be able to convert the subways without issue, and most of the branches too... it will mean building a viaduct through downtown Needham, or just digging it up for a subway or trench."
"No", she interrupts. "The villages of Needham must remain substantively unaltered with no prolonged disruption. This is also a measure of national security."
"...how is that a matter of national security, Madam President?"
"That is classified on a need-to-know basis."
"...and I don't 'need to know'?" you say skeptically.
"You do not."
You puff out your cheeks and exhale. "Well, if that's a priority to leave Needham untouched, the light rail tracks can just remain in situ, we'll power down the wires and halt service --"
"No," the President interrupts again. "Needham must also remain served by rail transit, with minimized degradation of service."
"A matter of national security, is it?" you ask.
She nods. "Exactly."
~~~
In the past,
I've argued against the conversion of the D Branch to heavy rail due to its impact on a potential branch to Needham. The D Branch is largely grade-separated (a prerequisite for modern HRT), but the Needham Line travels at grade through downtown Needham. As alluded to above, grade separating the downtown portion would require a costly/disruptive viaduct, tunnel, or trench.
But recent talk of a "Needham Trolley", pinging between a Green Line station at Needham Junction and an Orange Line station near Millennium Park (h/t to
@TheRatmeister, though I think there are others that aren't coming to mind), made me look again, and notice something that should've been obvious to me years ago:
Needham has four train stations.
Three of them can be served via (mostly) grade-separated ROWs. Screenshot from OpenRailway Map:
(There would be an additional crossing, not marked here, at Oak Street in Newton Upper Falls.)
These crossing fall into three categories:
- A pedestrian grade crossing just west of Hersey
- Could be eliminated as part of a rebuild of Hersey station
- Street crossings at Oak, Gould, and Webster Streets
- Significantly more disruptive, but this corridor will require non-trivial work anyway to convert it to a rapid transit ROW. With careful planning, potentially the impact could be reduced
- Gould St might also get a station, which again offers options to fold a crossing into the station
- Grade crossings in downtown Needham
- Much harder
- Numerous residential abutters
- Short distances between crossings reduces running length for grades, making longer stretches of grade separation -- potentially over a mile, from Heights to Needham's Oak Street
That third category is the rub. But... Hersey, Junction, and Heights can all be reached
without touching the grade crossings in downtown: Heights via an extension from Newton Highlands, and the others via an Orange Line extension. It's only Needham Center that would require the downtown grade separation.
According to the 2018 passenger counts, the 4 stations in question have a combined ridership of 1,440 riders. Of these, less than 16% come from Center. To put another way,
84% of current Needham commuters could be served by grade separated rapid transit without build an el/tunnel/trench through downtown.
(And, in fact, the addition of a new station at Gould St may
expand access -- or at least increase the number of residents in walking distance of a station.)
So... in this distant, hypothetical future, in which there is no time for mitigations, no time to build community support... and in which there is somehow drastic urgency to run heavy rail over the Highland Branch... and all the other challenges of the LRT -> HRT conversion have been otherwise accounted for... in this scenario, it might just be viable to run HRT to Hersey, Junction, and Heights, and run a (cute) "Needham Trolley" between Heights and Junction, to serve downtown.
The large majority of riders would maintain their service. And while Center riders would need to transfer, a trolley could justify the addition of infill stops at Rosemary St and Oak St, improving pedestrian access to transit for more members of the community, and provide improved within-town transit in a downtown that is well-configured for heavy pedestrian and transit orientation.
As is hopefully obvious, this is a contingency plan for a contingency plan for a contingency plan. I remain steadfast in my opinion that a Green Line/Gold Line extension to Needham Junction remains the best way to serve Needham in the context of the larger system.
But... if you really had to... you could probably swing HRT to 85% of riders without needing to disrupt downtown.