Forget the gondola, there’s nowhere to put it
No room near South Station for the infrastructure needed
Unlike Elon Musk’s latest foray in to urban transportation, which involves several as yet non-existent technologies, the idea for a Summer Street gondola is something which at least has been built and operated successfully elsewhere. The principal features of gondola technology are pretty straightforward, offering an unremarkable combination of relatively slow, expensive, and low-capacity mobility. A gondola would probably attract some ridership between South Station and the Seaport, despite an inherent transfer penalty (the amount of time it takes to transfer from rail or bus to the gondola). But there’s a big problem that’s impossible to overcome: it has to stop somewhere, that somewhere has to be close to South Station, and there is no room near South Station for the kind of infrastructure a gondola system would require.
A typical ski resort gondola requires a large building with machinery for the gondola, room to get on and off, to queue, and to have tickets checked. It’s usually on the ground, but it’s a ski resort, not a city: there’s plenty of room to build. In Mexico City, the gondola stations are huge concrete structures built on land next to the narrow streets of the district (the narrow street width being the reason the city didn’t build a cheaper bus rapid transit line there, despite an extensive BRT network elsewhere in the region). They soar several stories with stairs, escalators, and elevators to move people in and out. Yet nowhere are they built over existing roadways, something which would be necessary for the proposed Seaport gondola above Summer Street.
Take a look at the sketch of a terminal the gondola supporters have put forth. It is sleek compared with the Mexico City version, being held up by a single support in the middle of Summer Street. This might be possible in another location, but directly below Summer Street between Dorchester Avenue and Atlantic Avenue lies the 1912 Cambridge-Dorchester Tunnel, better known as the Red Line. There is no way that the structure proposed in the gondola marketing materials could have this type of structural support because of the construction and long-term built-weight impacts on the Red Line tunnel and South Station Under concourse. This vision of a floating terminal being promoted by gondola backers would instead look a lot more like the old elevated Central Artery or the pre-1938 El tracks, and accurate renderings would probably not look bright and airy. We’d be returning to the days of elevated structures casting the streetscape into permanent gloom.
Then there’s vertical circulation, which is engineer-speak for getting people up and down between the street and the gondola. Think about South Station, just below: when you get off the Red Line, there are several stairs, escalators, and elevators to move crowds of people up and down. There are five separate “head houses” for South Station—one on each corner of Atlantic and Summer and the direct stairway in to South Station—plus two elevators. Vertical circulation is required to move people, but also to allow safe egress in case of an emergency. Yet the gondola rendering shown shows no stairs, escalators, or elevators. Beam me up, Scotty!
Without easy accessibility and convenient connections to existing transit, the whole idea falls flat on its face. Passengers who today can go from the Red Line to the Silver in one flight of stairs would have to navigate three, rising up above the street to get to the gondola. Without a terminal at South Station offering the convenience of easy accessibility, you’d have a white elephant unable to respond to genuine mobility needs.There are a number of other issues that make the feasibility of a Summer Street gondola unlikely, including significant resilience issues (any single issue along the line has the potential to put the entire line out), and an inherent inability to scale to meet increasing demand. But there may be no need to get that granular with the analysis because getting past this first essential engineering issue—building an elevated terminal in a manner that threads a very narrow needle in an area chock full of existing underground tunnels and protected public spaces—is simply not possible absent a completely different design concept from the one proffered by the gondola promoters.
Ari Ofsevit is an MIT graduate student who lives in Cambridge and serves on the board of TransitMatters.