Monday, September 12, 2016

A single letter costs the T $2–3 million every year

Every night in Downtown Boston at about 12:45 a.m., a procedure, in theory, occurs to allow passengers to transfer between trains downtown and not miss the last train. (This dance is called "East-West"; the name probably goes back decades.) Here's how it should work (note that this is from an operations standpoint; passengers transfer as they normally would):
  1. The final Green Line trains from Lechmere, Boston College, Cleveland Circle, Riverside and Heath Street arrive at Park Street. 
  2. The last southbound Orange Line train waits at State Street for the last inbound Blue Line train.
  3. Once it arrives, the Blue Line train continues to Bowdoin, loops, and waits at Government Center. The Orange Line train proceeds south to Downtown Crossing.
  4. The last Alewife Red Line train leaves Downtown Crossing when this Orange Line train arrives and runs to Park.
  5. Passengers at Park transfer between Red and Green Line trains. Once this occurs, these trains are released, and a domino effect takes place.
  6. When the Ashmont-bound Red Line train gets to Downtown Crossing, the Orange Line trains waiting there are released. (There's no guaranteed last connection for Braintree passengers.)
  7. When the northbound Orange Line train gets to State, the Blue Line train there is released. There is a second meet (which is not necessary) between this train and the Lechmere Car at North Station.
  8. This is what the last train ballet should look like (thanks
    to Mark Ebuña for the screen grabs). These trains would
    remain stationary for more than 20 minutes. And that's
    on a good night.
  9. As these trains propagate out through the system, 56 "w" trip buses (the schedule notation of "w" means that a given bus will wait for the last train, although a few schedules use other letters) wait for transfers before making their last trips outbound, completing the domino effect.
The rail portion of this ballet, again in theory, should take about 8 minutes. The last trains out of Park Street are scheduled out between 12:45 and 12:53 (the later times because four Green Line trains have to all leave in succession on a single track). The system can then be shut for the night, leaving a bit more than three hours for track maintenance before the first trains the next morning.

Unfortunately, in practice, that's not how it works. As Marc Ebuña tweet-stormed recently, it takes a whole lot longer. And this costs the T a lot of money.

The last train connection is not guaranteed for passengers to Heath Street (who can take the 39 bus, which is held for connections at Back Bay), but it is guaranteed for Lechmere. Since there's no layover at Heath Street (since the Arborway terminus was abandoned), these trains have to turn back in to layover at Lechmere. The last train to Heath Street leaves Park at 12:30, arrives Heath at 12:47, and turns back to Park, with a scheduled arrival of 1:06. (In 2007, this train was scheduled 10 minutes earlier, and the "w" note was not present as recently as 2013, although I believe the T has guaranteed these schedules before then.) And this train is given the "w" notation, so that while every other train should be—if they're on schedule—ready to depart at 12:45, they wait for another 21 minutes before making this connection. And if the Lechmere train is late? The trains still wait. On September 4, for example, the Red Line waited 40 minutes.

This letter costs the T at least $3 million per year. The "w" notation reads:
"Last trips wait at some stations, primarily downtown, for connecting
service. Departure times are approximate."
This is entirely unnecessary. Earlier Lechmere trains are just as able to make the connections. There's a train scheduled to arrive Park at 12:41. If this train were the "w" train, it could drop passengers at Park and continue to Lechmere; any later train could pick up any passenger waiting, but connections for arriving passengers on such a late train would not be guaranteed, other than for buses meeting this train at Lechmere. Or these trains could be operated as non-revenue services, and the 39 bus, which connects inbound with trains at Copley, could provide this service. Other than a few late riders inbound on the E Line, no passengers would be adversely impacted, while every other passenger on the system waiting at least 20 extra minutes (the earliest the last Red Line has left Park Street in the past 30 days has been 1:09, the average has been 1:19—thanks for the coding from @MBTAinfo) would benefit. I'm usually not one to advocate for earlier service, but in this case, either publish a later, more truthful schedule, or run the service on time.

Then there are the costs, which cascade very quickly through the system, since the single Lechmere trip which operates late causes trains on every other line, and 56 bus trips, to all experience delays of at least 20 minutes. But the operators still get paid (overtime, in fact) and the power stays on and the inspectors keep the stations open and the operations staff stays on duty until the last trains pull in. It costs nearly as much money to keep a train stationary as it does to run it, and with overtime, it may cost more. In 2014, the T reported that a bus cost $178 per hour to operate, a heavy rail car $240 and a light rail car $264. Giving them the benefit of the doubt that they're operating single car green line trains, the cost per hour of four light rail cars (B, C, D and Mattapan), 30 heavy rail cars (five trains at six cars each) and 56 buses comes to $18,224 per hour, or $304 per minute. If the Lechmere car causes a 21 minute delay (as scheduled), this costs $6,384 per day, or $2.33 million per year. In fact, the average delay is more on the order of 34 minutes, which costs $3.77 million. This assumes that all delays are caused by the late Lechmere car; if we attribute 20% of the delays to other causes, there is still a direct operating cost of 1.9 to 3 million dollars per year. (These costs are likely even higher now.)

Two to three million dollars. All because of a "w" on the schedule.

But it gets worse. The T has precious little time between the end of service and the first trains the next morning; most lines aren't scheduled to be cleared for powering down or work until about 1:30, leaving only about three hours and thirty minutes until service starts in the morning. A 20 to 30 minute delay accounts for 10 to 15% of this time, meaning work crews have to wait for this unnecessary delay before performing maintenance.

Then there are the passengers. If you take the last train, the schedule—and any real time data—will show it coming at a certain time. But you'll either wind up standing on a platform for 20 to 30 extra minutes, or sitting on the train downtown for that amount of time. There is probably significant ridership loss from people who know how long the wait takes, and choose another mode. This fare revenue is probably minimal in relation to the operating costs, but certainly not zero, but the impact to passengers is more drastic. If we assume just 10 passengers per rail car and two additional passengers on each bus who don't transfer from a train), it amounts to 450 passengers each inconvenienced by 20 to 30 minutes. That adds up to 150 to 225 hours per night, or 50 to 75 thousand hours per year.

The FMCB's response to a budget gap has been to push privatization, which is not guaranteed to fill any such gap, but will draw the ire of the unions and potentially degrade service. Yet various measures which this page has noted have fallen upon deaf ears. There's a lot of money to be saved at the T. There's a lot of very low-hanging fruit. (Like publishing a set of schedules without a "w" for the 12:47 departure from Heath Street. And who reads paper schedules, anyway?) This problem would be very easy to fix: the next schedules would be amended with a different note for the E Line, perhaps "x: last trip making connection downtown departs Heath Street at 12:25."

Making that change would go a long way towards paying for real, actual overnight service.

[Thanks to James Jay for noticing this, Marc Ebuña for burning the midnight oil, @MBTAinfo for the code and Stefan! for the maps.)

Wednesday, September 7, 2016

How MassDOT stacks the deck: Red-Blue edition

The Red-Blue connector is probably the biggest bang-for-your-buck piece of rail infrastructure in the Commonwealth of Massachusetts. With 1300 feet (¼ of a mile) of new subway, it would both provide a much better connection between East Boston, the airport and and the Red Line and serve as a major core capacity project. From the south, the Red Line, at rush hour, operates at peak capacity through downtown to Charles; as it drops passengers at South Station, Downtown Crossing and Park, it takes on transferring passengers and the load stays high. At Charles, however, there are many more destinations than origins, and demand drops. Right now, all Blue Line passengers destined for Kendall or beyond are forced on to the Green or Orange line and the Red Line at this high-utilization point. The Red-Blue connector would allow them to bypass this downtown congestion, reducing the strain on the near- or at-capacity central portion of the subway network. (Oh, and it would also allow a rethinking of Cambridge Street, which is incredibly dangerous for anyone not driving a car. But it has a pretty median.)

This page, in the past, has suggested that it may be cheaper to build an elevated Red-Blue connector, and also cast doubt (twice!) on the MassDOT's cost estimates. Their claim is that it would cost $750 million to make the extension; which is a cost per mile of $3 billion. This per-mile cost is double the cost of recent tunnel projects in Seattle and San Francisco (where, as you may be aware, they have earthquakes) and even more than the Second Avenue Subway in New York. It's a completely outlandish number.

And this is entirely by design.

The state is required to plan the Red-Blue connector, but they're not actually required to build it. Because MassDOT is, at some levels, a morass of incompetence (see Extension, Green Line), they operate under the assumption that nothing new should ever be built, even if there are dramatic improvements to the overall transportation network. Remember, these are the same people who look at ridership growth and declare it "basically flat." But not only do they want to do as little as possible, they actively stack the deck against their designs to come in so costly that they don't make sense to build. This is the idea: inflate the cost so much that it would not make any sense to build. It's deceitful. It's duplicitous. And at MassDOT, it's standard operating procedure.


(On the other hand, when MassDOT—or MassHighway—wants to build something, like the outlandish mutil-tunneling of rail lines in Dorchester to add highway capacity to the Southeast Expressway, they don't bother to put forth a cost estimate. Or remember when we didn't add a lane to 128 because it was going to cost too much? Yeah, me neither.)

Here's how it's done. As we discussed, there is an existing tunnel to Joy Street which was used until the 1950s to move East Boston cars to the old Bennett Street Yards in Harvard Square for heavy maintenance. The obvious solution is to use as much of this tunnel as possible—both to minimize digging in the street and to minimize disruption to current service—yet the state's two alternatives don't use it at all. Instead, with minimal justification, they propose a half-mile-long deep bore tunnel 50 feet below grade, tying in with the existing tunnel just west of Government Center. Using tunnel boring machines (TBM) makes sense for tunnels of any length, as the impact to the surface is significantly less. It is also, for longer tunnels, significantly cheaper than cut-and-cover methods. It's fine to have that as one alternative—there are certainly advantages to using a TBM—but the fact that the alternative analysis only mentions TBMs makes it, well, not really an alternatives analysis at all.

The benefits of a TBM, however, only accrue for longer tunnels. The marginal cost of an extra foot of TBM tunnel is relatively low, but the initial cost is very high. A cut-and-cover tunnel here would require 1300 feet surface impact. Using a TBM would require less, but only slightly. Why? Because you still have to dig launch and recovery boxes for the TBM, and where the tunnel needs to be wider for stations or crossovers, it has to be dug out. Considering the substrate in Boston (mud and clay) a TBM would have to build concrete rings as it digs, and any stations or crossovers between the tunnels would have to be dug out separately. And while the total disruption would be somewhat less than a cut-and-cover tunnel, the disruption would be more spread out and extend much further, from Charles Circle to or beyond Government Center, rather than from Charles to Joy Street. Utilities would be affected in either scheme, and it's possible that fewer utilities would be affected by a more-contained scheme between Charles Circle and Joy Street.

So in addition to carving up nearly as much street space, and over a longer distance, you'd also incur the cost of using a tunnel boring machine (they're not cheap). You'd be building nearly a mile of new tunnel, while only incurring the benefit of about a quarter of that. And the costs are therefore much higher. This only makes sense if you don't actually want to ever build anything. [Update 11/2017: I've heard through the grape vine that part of the reason only TBMs were analyzed is that Mayor Menino didn't want anyone digging up the new streetscape on Charles Street, which he liked. The trees are nice for people driving cars, I guess.]

MassDOT's plan would also build tail tracks under Charles Circle beyond the station. Tail tracks are important: it allows a terminal to continue to operate at full capacity even if a train is incapacitated: it can be shoved in to the tail track and out of the way until the end of service (or until service levels are decreased). However, they take up a good deal of space. This is less of an issue if there is extra space (like there is at Forest Hills, Wonderland or Oak Grove) or at Alewife, where the line was originally built to extend to Arlington (the tail tracks actually do cross the border). But in downtown Boston, the tail tracks require significant extra tunneling under Charles Circle, which is expensive and disruptive.

A different, more outside-the-box option is to create a "pocket track" before the final station. This serves the same purpose as the tail track—train storage near the end of the line—but rather than two long tails, it is in the middle of the two tracks short of the station. All this requires is that the tunnel be built wider here (the same width as the platform to the west requires) for this staging track. Additionally, by utilizing the existing layout at Bowdoin (with, perhaps, some modification for longer trains inbound, or even converting the station to outbound service only), the line would retain the utility of the loop there, which is eliminated in both of the state's alternatives. While this does result in slower operation in and out of the station, it allows redundancy for turning trains: if there is any congestion or another issue at Bowdoin, some or all trains can be turned temporarily at Government Center to maintain service on the rest of the line. Eliminating this loop eliminates any such redundancy. A pocket track and the retention of the loop are nearly impossible with a bored tunnel but with cut-and-cover simply requires a somewhat wider dig.

By requiring long-term construction closure of the line west of Government Center, the state's plan would also require new construction of a terminal station there. Government Center does have a crossover to its east, but it is a single crossover, which would not be able to handle the rush hour Blue Line schedule. This would require a new double crossover to be installed in what is a narrow section of tunnel. Utilizing the existing tunnel past Bowdoin would preclude this extra cost, as trains could continue to loop there during construction. There would be no disruption when the extension opened—not even a weekend shutdown to tie in new tracks. The same can't be said for the State's scheme.

State's plan in red, my plan in blue.
Here's a quick rundown on the major elements required to build the state's version of the Red-Blue Connector:
  • A launch box for the TBM
  • Cut-and-cover tail tracks west of Charles Station
  • Main access to the Charles Station (planned 50' below grade)
  • Charles Station, proposed as a sequentially excavated cavern but with no explanation of how that will be done in the fill-and-clay substrate in the area.
  • Emergency egress from Charles Station
  • Crossovers east of Charles Station
  • New Bowdoin Station (alternative 2 only)
  • Modification of existing Bowdoin Station and trackage to serve as ventillation (alternative 1 only)
  • Receiving shaft for Bowdoin station
  • Cut-and-cover track for connection to existing track at Government Center
  • New crossover west of Government Center to allow it to serve as a terminal station
  • Total cut-and-cover of approximately 800 feet, assuming the Charles Station can be built below grade (I'm skeptical).
And here's a rundown of the elements required for a cut-and-cover tunnel from Joy Street to Charles Circle:
  • Main access to Charles Station (20' below grade)
  • Charles Station cut-and-cover
  • Secondary access to Charles Station (possible because it would require only 20' of vertical circulation, rather than 50')
  • Cut-and-cover crossovers and pocket track
  • Cut-and-cover connection to existing tail tracks at Joy Street
Here's my total-guess cost estimate for the cut-and-cover costs (and I think many of these are quite high):

1. Utility Relocation: 0.25 miles at $100m/mi = $25m
2. Cut-and-cover tunnel (mostly 40' wide): 0.25 mi at $600m/mi = $150m
3. Rail systems: 0.25 mi at $100m/mi = $25m
4. Egress, NFP130, etc: 0.25 mi at $200m/mi = $50m
5. Station, 1 at $50m = $50m
6. Street rebuilding, 0.33 mi at $75m/mi = $25m

This totals to $375 million, or half of what the state's plan would cost. There's no way to know much the state thinks it would cost, because they didn't bother to analyze this alternative as part of their alternatives analysis.

Now, the state did address the difference in cost between a bored tunnel and a cut-and-cover tunnel. Well, sort of. The draft environmental impact report has the clause:
The resulting total cost (direct plus offsets) to construct a cut-and -cover tunnel shell is about 1.2 times the cost of the mined tunnel method. This differential may slightly decrease when the balance of construction scope (e.g., station components common to both Build Alternatives) is considered. Based on this relative cost differential and the associated environmental and social impacts, schemes utilizing mining methods were selected for further development and evaluation. 
Uh, this isn't really how an alternatives analysis works. In a complex construction project, 20% is basically a margin of error. As we've seen in some other deep boring construction, it's not uncommon to have an unforeseen obstruction which can dramatically increase the cost of a project. This can also be an issue with a cut-and-cover tunnel, although Cambridge Street was widened in the 1920s so the utilities there are a bit less complex than the centuries-old sewers under many Boston streets. The point of an alternatives analysis is too look at different alternatives and see which is the most appropriate. In this case, there are not enough alternatives, and very little actual analysis. I wouldn't be surprised if a full analysis showed that 1300 feet of a cut-and-cover tunnel was a good deal less expensive than twice as much deep bore tunnel and the additional track connections involved.

And there is no information in this report about how they are going to build the Charles Blue Line Station 50 feet underground in the substrate of Boston with sequential mining. The Second Avenue Subway is being built in hard Manhattan schist which can be blasted apart while still maintaining structural integrity above. I'm not an engineer with this sort of experience, but given that there is no explanation of how it would take place, I'd have to doubt its veracity. The current idea is explained that the tunnels would be bored and then the station areas would be mined out in between the bored tunnels, using their structure to support the road above. I guess that could work. But it seems to add several steps (and thus increase the cost) by building the tunnels only to hack them apart to build space for stations and crossovers in between. When asked in 2011 if it was inflating the costs of the project, MassDOT was very defensive in claiming that they weren't, and that Very Important People said the same thing, yet they didn't actually explain why they chose the scheme that they did (beyond "we hired someone") and as I outline here, it seems they put their thumb on the scale.

Even giving them the benefit of the doubt that a bored tunnel is the best option, the cost estimates seem out of hand. The cost of the 72nd Street Station cavern—which is 1300 feet long, the length of the Red-Blue connector from Charles to Joy Street—plus the track connections to 63rd Street is $431 million, significantly less than the Red-Blue connector. This, for a project taking place 100 feet below the street in New York City, which may be the most expensive construction market in the world.

To put it another way, I find it very hard to fathom that a ¼ mile cut-and-cover tunnel with a single station (for which the headhouse is already built) connecting in to an existing tunnel would cost three quarters of a billion dollars. Or $3 billion per mile. Some more comparisons? The cost of the Longfellow Bridge—twice as long, and rebuilding a century-old bridge while maintaining transit service—is one third the projected cost of Red-Blue. That can't be right. The Big Dig cost less than $3 billion per mile, to build highway tunnels three times as wide, over and under several active railroad tunnels, with more ventilation and dozens of ramps. And the Red-Blue connector would cost as much? Please.

A layman's staging plan for Red-Blue. Simplified, a bit.

A layman's plan (as follows) would involve a shallow cut-and-cover tunnel, likely using slurry walls to support the excavation. (See Dig, Big). The tunnel would be 40 feet wide at the Charles Station and to the east for the crossovers and the pocket track, where it would taper to 20 feet for the connection to the existing trackage at Joy Street. The Cambridge Street roadway is at least 64' wide between Charles Circle and Joy Street; with parking it is 80 feet wide. Assuming the construction could be completed in two phases (two 20-foot-wide excavations) with a 5 foot buffer around each, this would leave 34 feet for road for traffic during any construction, enough for two lanes of travel in each direction (or two in one direction, one in the other and an emergency vehicle access lane). Cambridge Street is currently a horror show for cyclists and not much better for pedestrians, and the project would allow a complete street to be built in its stead.

See larger-size file here
Would there be traffic headaches during construction? Sure, just as there have been with the Longfellow Bridge adjacent to the project area. Would it be apocalyptic? Much like the Longfellow, it would not. And the effects would stretch only from Charles Circle to Joy Street, rather than the state's plan, which would have impacts extending from west of Charles Circle to Government Center, at least. In any case, either scheme will have short term traffic issues, but a long-term benefit, both with fewer vehicles and the potential to build a "complete street" with separated bicycling facilities and better pedestrian facilities. And get rid of the damn median!

There is no logical reason that the Red-Blue connector should be, per mile, the most expensive subway construction in the country. Unless it's by design. And—yes, to point a finger at MassDOT—that's exactly what I think has happened.

tl;dr: this is why we can't have nice things.