Tuesday, May 12, 2009

Ugh … the Silver Line

Originally posted as a comment on The Transport Politic. I'm sure I'll write about the Silver Line again.

The Silver Line has so many problems.

First off, there's this bizarre notion that people from Roxbury and Mattapan need to get to the airport. All the time, forever. It's probably not the case. I'm not one to make brash generalizations, but here's one: the people who generally use the airport are folks from affluent and/or student-infested parts of Boston. At higher rates, anyway, than the Roxbury-Mattapan. For this community, access to downtown Boston and better-than-bus service is probably paramount. It would make much more sense to take this $114m and build a spur of the blue line in to the actual airport. Build a loop to the terminals. Heck, build it in to Central Parking, where there are elevated walkways to all the terminals. Eliminate the shuttle bus (which I once tried to take before a long weekend and it was packed to the gills with college students with dozens more waiting to board).

View Logan Blue Line Spur in a larger map

Second, the Silver Line from South Station to the airport is very slow. The tunnel is fast enough—the speed is slow but it's grade separated, so it works. The problems arise once the buses reach the surface. The then cross D Street and proceed to drop the trolley poles and switch to petroleum. The route then takes a convoluted backtrack loop back towards South Station, across D Street, through several lights, before the bus can finally turn down in to the tunnel. $15b and they couldn't build a ramp straight to the airport, which would have been rapid.

Then, the airport. Since Boston is the furthest northeast city in the country, Logan has never developed in to a hub airport. Thus, no one has ever built one big terminal. So the airport is a hodgepodge of terminals, each with an access road which gets choked with traffic. Sure, the buses can sometimes bypass these queues, but they still have to go through the loops in to terminals A, B, C, and E (with two stops in B—Terminal D doesn't really exist). Ten of fifteen minutes later, they loop back in to the tunnel and a mess of roads before looping back to South Station.

I'm very glad that "Phase III" has been all but nixed by the Feds. A $1.4b tunnel would not fix the main issue that trips are scheduled to take 38 minutes to go from South Station to the airport and back. As the crow flies, this is just over a mile. A Blue Line spur to the airport, with stops at Maverick and Aquarium, would tie in to the rest of the system with trip times of maybe eight minutes, tops, with faster loading and more capacity, to boot.


But that's really actually not the worst part. Again, I'll start by explaining that I am happy that the $1.4b tunnel from pretty much nowhere to pretty much nowhere with a couple sharp curves thrown in was not funded. From Boylston Station on the Green Line five blocks south is a disused tunnel for streetcars, and the plan was to basically decimate that tunnel to build it to bus loading gauge. Here's the thing—the tunnel ties in to the Green Line—to a four track alignment to Park Street Station—and is grade separated, underground!, at the junction. Basically, if you turn back one line of the green line at Park Street, you could add in another without increasing capacity on the congested central subway.

And this tunnel would tie in splendidly with light rail down towards Mattipan. You build a new portal at Tremont and Oak and cut diagonally across the Turnpike and NEC from Shawmut to Washington. Washington Street is wide enough for trolley cars to not interfere with parked cars by occupying the center lanes. (Washington Street once had the elevated above it.) Stations in the center of the tracks, proof of payment ticketing perhaps, and you don't impede traffic significantly, which could pass stopped trains.

Getting through Roxbury might be fun—but you could use the old elevated right-of-way for one or both tracks of a light rail line. Or tunnel underneath if you had the dollars. From there, Warren Street has two lanes each way plus a wide median, so congestion wouldn't be a major issue) to Quincy Street, where you'd then have to build on a two-lanes-plus parking street to Blue Hill Avenue for less than half a mile. Cut parking to one side of the street and build wide lanes and you'd be fine.

Then you hit Blue Hill Avenue. The Avenue is three lanes each way plus a wide median all the way down to Mattapan, where you could connect with the High Speed Line. Trolley tracks could be in a separate median (like Comm Av or Beacon Street in Brighton and Brookline). In fact, this was the case in the past.

View Boylston-Roxbury-Mattapan in a larger map

For a heck of a lot less than 1.4b. (Portland can build a streetcar for $25m/mile. This is 7.5 miles. Make that $30, throw in $50 for a new portal at Tremont and $25m for a bridge across the Pike, and the cost is $300m.


  1. Good post. I think a better idea than another surface trolley is to run a second branch of the Orange Line, starting right after New England Medical Center, under Wash. St. to Dudley, then underground to Grove Hall to Blue Hill Ave., where it could either run on the surface in the median or in an open cut as the other Orange Line does now. Orange Line is faster than Green Line and has more capacity to expand. Yes, this would cost, but it would be a worthwhile investment and planning should start now so it can be funded and built when the economy improves.

  2. One should remember that the airport is not only a place for air transport but also employment. Perhaps more affluent folks fly, but less affluent folks work there, and folks who work there make daily trips, rather than the occasional trip.

  3. I had an engineering student friend a few years back who did an analysis of the green line/silver line situation for a paper. What he found from taking a good hard look at the details was that Silver Line as proposed previously (with tunnel connector) and the green line both make 90 degree turns near Boylston, making an X shape of sorts.

    His proposed solution was to have the Silver Line be light rail on the same gage tracks as the green line and to eliminate the curves, so that the Silver Line would come straight down from Washington Street and carry on to Lechmere and the Green Line would go straight from Boylston St. to South Station and then the airport. Makes a lot of sense to me.

  4. @ Gene:An Orange Line Branch would be nice, but the construction would be hugely expensive and disruptive. With current construction technologies, light rail can be built relatively quickly and easily at-grade, and along most of this route, it is wide enough to build it without completely closing the street. Tunneling would either be deep-bore (very, very expensive, look at the Second Avenue Subway in New York) or cut-and-cover (less, but still quite, expensive, and very disruptive to the street). I could see a short tunnel through Roxbury a la the Harvard Tunnel (originally for streetcars) but tunneling the whole thing is probably not cost effective.

    @ Phil:Yes, I totally understand this. What I probably could have made clearer is that for years the T touted a $1.4 billion tunnel as "a one seat ride from Dudley to the airport" and I thought to myself "Hmm, is that the top priority for Boston transportation?"

    With the cost of driving and parking in Boston, many lower income airport workers already take the T to the airport, but are hamstrung with egregious Silver Line routings or the lack of a good connection from the Blue Line. If Blue Hill Avenue was a light rail which fed in to the central subway it would connect at Government Center, which would then be an eight minute ride, perhaps, to the airport. From Boylston, this would be twelve minutes of travel time, plus the transfer. However, the service to this transfer station, downtown, and other lines would be vastly improved. In addition, this would provide better access to downtown and beyond, also centers of employment for all levels of incomes.

    Finally, I would contend that number of airport transit riders would be increased more by a blue line extension than a Silver Line connection. This is not to sound classist at all, but without a direct rail connection to the airport (meaning a slow, crowded bus from South Station or a slow, crowded bus from the Airport station), higher-income travelers are less likely to take transit, clogging congested tunnels with cabs and livery. If you build an airport station, it would make the trip from Downtown faster by rail, and appeal to this sector.

    In other words, for employees at the airport, cost is the main driver of their transportation choices. Decreasing the time slightly will not gain many new riders--most are likely already on board (so to speak). And the Silver Line would still be slow and uncomfortable enough, even with a $1.5b tunnel, that it would not attract many other riders. Higher-income folks, for trips to the airport, value their time more (If you make $50 an hour your time is, economically speaking, worth more than if you make $10.) and would take the train, but only it were time-competitive.

    @JasonI've had an idea like that, too, from time to time, but for a couple reasons I think it would be really hard to work out:

    1) The Green Line is over capacity. Many riders go from Kenmore (and points west) to Park Street and Government Center. While some do transfer there to the Red and Blue Lines, many disembark there to access offices, shopping and other services. If these trains went due east, they'd cut out a good portion of this market, and perhaps lead to more congestion.

    2) Light rail to the airport would be quite difficult for a couple of reasons. The main one is that you'd have to convince Mass Highway and the Interstate (Federal) highway folks to allow light rail tracks in the Ted Williams Tunnel. This would be, well, difficult, to say the least.

    3) If you got #2 allowed, you'd then have to connect the tracks from the Silver Line tunnel (assuming its loading gauge could support green line vehicles) to the Ted.

    4) And then you'd have to build them up in to the airport.

    5) The other issue would be the connection at Boylston. The tunnels there are very, very old and very, very cramped--that is the original section of tunnel dating from 1897. If you build this there would be a lot of disruptive construction, and you'd somehow have to do it without cutting off Green Line service. This would likely cause costs to skyrocket. The beauty of using the existing tunnels south towards Washington is that they are already grade-separated in to Boylston, and except for a portal, would not require any new tunneling. Tunneling, as I mentioned above, is very, very expensive.