Red-Blue connector: think outside the tunnel

We recently wrote about the obscenely inflated cost of the Red-Blue Connector. And while the underground costs are certainly inflated, it still involves building a tunnel underground, in loose fill, under a busy street, and then building connections in to an existing station. It would still involve months- if not years-long lane closures, massive utility relocation, and underground station construction. It might be heretic to say so, after Boston has mostly removed above ground transit, but in this case, an elevated solution might be the best solution possible, and not just because it would be cheaper (which it would be).

First, the logistics. The Blue Line tunnel currently ends several blocks east of Bowdoin Station. The original portal was between Joy and Russell Streets (at Nims Square, one of Boston's lesser-known squares). Here's an aerial photograph of the portal; you can see that it is several blocks east of the curve at Bowdoin Station. Most likely, the tracks were capped just east of Joy Street, and the portal filled with dirt and built over. Most likely, it still exists.

And most likely, it could be easily opened. The cheapest option would be to run the Blue Line straight down the center of Cambridge Street at grade, but for a litany of reasons that, uh, wouldn't work. But instead of coming up from underground and flattening out, it could continue sloping upwards and, by Blossom Street, enter an elevated guideway above Cambridge Street. From there, it would continue a few hundred feet and terminate at a two-track station with a center platform above Cambridge Street, adjacent to the current Charles Station.

Click the diagram below to enlarge. All lines are to scale.

There are many, many advantages to an elevated solution. They include:

• The portal exists! There may be some utilities buried there, but not likely major infrastructure; it's probably mostly just fill.

• The portal is built in to the side of Beacon Hill. As the tunnel rises to the surface, the surface falls away. This limits the space that a ramp takes up for the transition from underground to elevated. In addition, because the Blue Line does not require overhead wiring, the tunnel height is lower—and therefore the floor is higher—reducing the amount of climb necessary. A similar subway-to-elevated transition exists for Green Line trains between North Station and the Lechmere viaduct. The distance between the portal and where the viaduct passes over the ramps from the Leverett Circle is conveniently the exact same distance as from Joy Street to Blossom Street on Cambridge Street.

• Once above the street, the viaduct will be quite narrow. Since the East Boston tunnel was originally built for streetcars, Blue Line cars are narrower than, say, Red Line cars. The elevated portion of the Green Line between North Station and Lechmere—especially the new section east of Science Park—is a good guide to the width, although with no need for overhead wire, a Blue Line viaduct could actually be built narrower than the Green Line.

• Charles Station could be built to serve the Blue Line with no added mechanical equipment, and minimal changes to the station. There are already wide stairwells, escalators and elevators in Charles Station which bring passengers from street level to the Red Line. The Blue Line would simply be a platform accessible from the current outbound platform, and would not require any additional infrastructure. Unlike other transfer points in downtown Boston, Charles Station was recently rebuilt, and passages are wide enough for significant additional traffic. An underground station, with additional elevators and escalators

• An elevated Charles Station would require transferring passengers to climb and descend fewer stairs than an underground solution. Imagine a round trip from Cambridge to East Boston. For an underground station, passengers would arrive on the Red Line, descend to street level and then down to the underground, reversing the trip on the way back for a total of four flights of stairs. For an elevated solution, the morning would require two flights—down to street level to cross under the Red Line and then back up—but the evening would be a level transfer, halving the vertical distance each passenger would have to travel.

• While Cambridge Street abuts the historic Beacon Hill neighborhood, it is generally bordered by newer construction, and in many cases by parking lots. The street runs east-west, so most of the shadows cast by an elevated structure would fall on the north side of the street, which is mostly occupied by Massachusetts General Hospital, and in several cases by parking facilities. As a major beneficiary of the project, MGH would likely be willing to have some shadows cast in exchange for far better accessibility. In addition, Cambridge Street already has an elevated structure at Charles Circle, so it is not an entirely new concept to have overhead transit in the area.

• A fire station would likely have to be relocated from the south side of the street between Russell and Joy Streets as they would no longer be able to take left turns across the subway-elevated transition. However, it could be moved to parking facilities on the other side street near MGH, and integrated in to new construction. For instance, a fire house occupies the ground floor of a skyscraper in the Financial District.

• Elevated construction and stations are far less expensive to build than underground. And far less distuptive. While an underground structure would require years of lane closures on Cambridge Street, an elevated structure would require only supports to be built in ground—and those would be in the median. Most of this work—exploration, utility relocation and the pouring of the concrete—could take place outside of rush hours, and the actual viaduct could be built off-site and placed on the pedestals, with minimal interference with local traffic. If the area can survive a three-year closure of the Longfellow Bridge, it could deal with a few short-term lane restrictions.

At $100 million per mile, the elevated section would cost less than $50 million to build. Since the station would be little more than a concrete slab between two tracks—no need to install multiple elevators, escalators and fare control—it would not appreciably add to the cost. It's entirely possible than an elevated solution could be built for under nine figures, far, far less than the state's estimate for an underground connection.

• This project would require few—if any—property takings. The only street-level construction would be supports for the elevated, and these could be built in the existing median on Cambridge Street. Again, the supports for the Green Line connection between Science Park and North Station is a good case study; the base of the concrete pedestals are only five feet wide.

Building a Red-Blue connector is something which would dramatically enhance Boston's transportation network. It would increase ridership, reduce congestion downtown, and provide better employment access for a large part of the area. It would also utilize the only portion of the downtown network which is under capacity—the Blue Line—and allow it to better serve the traveling public. And while the state may be set on inflating the price to high that it will never be built, a compromise solution using as much existing infrastructure as possible could be built more quickly and far less expensively. It is a solution the city and state—and stakeholders in the area—should seriously consider.

Red-Blue Connector: It costs how much?

The Commonwealth of Massachusetts is supposed to build a connection between the Red and Blue lines. But they really, really don't want to. It's probably a very good idea, since it will increase mobility for Blue Line riders accessing jobs in Cambridge. And it will take some of the capacity crunch off the core subway lines where Red-Blue transfers take place. And it will improve access to Logan Airport. And it will shorten trips for thousands of commuters each day who will no longer have to transfer twice, in already-crowded downtown stations. There are definitely benefits. And the state is supposed to build it.

They're doing their best not to. They've claimed that the construction would cost $750 million, which has been called "deliberately high." How deliberate? The costliest subway project in the country—the Second Avenue Subway in New York—costs 1.7 billion dollars per mile. The Red-Blue connector is 1500 feet long. Less than a third of a mile If you do the math, it comes in at $2.7 billion. That's not even in the ballpark. It's an obscene figure and is risible. It shows the state does not want to come close to making a good-faith effort to support this transportation connection.

How much would it cost? Well, likely far less. The current Blue Line tunnels extend underneath Cambridge Street to a former portal at Joy Street. Continuing the tunnel would certainly be disruptive, but could be done in a cut-and-cover method without fully disrupting traffic flow (the street is five lanes wide including the median, and the subway would only require two). Utilities would require movement, but there would be no need to support an elevated roadway or surface train lines above (like the Big Dig). Traffic on Cambridge Street would suffer for a time, but better transit service in the end would be worthwhile. Alon Levy has a compendium of subway construction costs, and most projects fall under $1.5 billion per mile.

A good analog might be the Central Subway in San Francisco. It's a short extension of a light rail-sized transit line (as is the Blue Line; the East Boston tunnel was originally built for streetcars so it's a much smaller gauge than, say, the Red Line) extending to a terminal station in a dense city. It is budgeted for $800 million per mile. If the Red-Blue Connector was built for the same cost, it would come in around $250 million. Or a third of the cost the state estimates.

The $750 million figure is not disingenuous. It's a lie. And an elevated connection—with only a few hundred feet of elevated structure—could be built for a fraction of the cost with a better final product, to boot.

Crosby's Corner: something to like for cyclists

If you drive out Route 2 like I did this weekend (twice, because I misremembered the date for a ski race), you'll notice some construction near the border of Lincoln and Concord. This is Crosby's Corner, and it's an example of a highway project which will likely benefit all users, and which is the right kind of construction to do in this day and age. It's always a breath of fresh air to remember that MassDOT secretary Rich Davey has said that we're not building any more highways. But it's the right policy: fix and streamline what you have so that it serves the people who use it.

So, Crosby's Corner. It's the second light on Route 2 past 128, where, going outbound, you come down a hill and take a left. It's certainly not what you'd think of being a safe design, but it dates from the 1930s when there was far less traffic than today. Now it is a backup-causing bottleneck (one of several on Route 2) and probably the most dangerous intersection on the road. Outbound, there's the left turn light at the bottom of a hill. Inbound, there's a sharp right at the bottom of a hill and then a left-hand merge with no merge space. There have been some pretty horrendous accidents, and it is only a matter of time until the next one.

The plans for improvements are generally good. A few houses were taken for the construction, which will take up more space than the current roadway, although it won't feel like a superhighway interchange. What excites me most, however, is that for the first time in nearly a century, bicyclists will be able to get from Route 2A to Sandy Pond Road, filling a major gap in the cycling network.

Some of the best bicycling in the region is north and west of Boston. Once you get past 128, the rolling country roads of Lincoln, Concord and beyond are a cyclists dream: they're too narrow for high speed driving, and twisty enough that (for the most part) they don't form direct enough routes to be amenable for through traffic. The one downside is Route 2: while there are some crossing points, there are several areas where access is, for all intents and purposes, limited to cars. (Route 2 is not a limited access freeway, and bicycling would be technically legal, but it would be extraordinarily dangerous.)

I will admit that the Crosby's Corner area is not currently, nor will it ever be, a major bike commuting corridor. But it will connect Sandy Pond Road, a beautiful, low-traffic roadway, to 2A, a more heavily-used thoroughfare, but one with enough of a shoulder to be amenable to cyclists. On my evening summer rides, I often face the question of cutting across Route 2 on Bedford Road, or adding 6 miles to my ride to head out to Concord center, and then back on Route 126. Taking Sandy Pond Road would be great, but would require a 100 yard ride on and then left turn across Route 2, unfeasable even over such a short distance. The new plans will allow cyclists to cross under Route 2 and then take a somewhat roundabout route to Sandy Pond Road. While the current plans don't mention it, a short cycletrack-like path from Sandy Pond Road along the Route 2 shoulder would better facilitate bicycling movements. This should be a goal of the project, as it would be an inexpensive way to work in dramatic bicycle improvements for a $60 million highway project.