Boston has two main train stations: South Station, and North Station. Both are terminals, about 2 km apart, each serving its own set of suburbs; as a result, over the last few decades there have been calls to unify the system with a regional rail tunnel connecting the two systems. This tunnel, called the North-South Rail Link, or NSRL, would have been part of the Big Dig if its costs hadn’t run over; as it were, the Big Dig reserved space deep underground for two large bores, in which there is clean dirt with no archeological or geotechnical surprises. The NSRL project had languished due to Massachusetts’ unwillingness to spend the money on it, always understood to be in the billions, but in the last few years the pressure to build it intensified, and the state agreed to fund a small feasibility study.

A presentation of the draft study came out two days ago, and is hogwash. It claims on flimsy pretext that NSRL would cost $17 billion for the tunnel alone. It also makes assumptions on service patterns (such as manual door opening) that are decades out of date not just in Europe and East Asia but also in New York. The Fiscal and Management Control Board, or FMCB, discusses it here; there’s a livestream as well as a link to a presentation of the draft study.

The content of the study is so weak that it has to have been deliberate. The governor does not want it built because of its complexity, no matter how high its benefits. Thus, the state produced a report that sandbags a project it doesn’t want to build. People should be fired over this, starting with planners at the state’s Office of Transportation Planning, which was responsible for the study. The way forward remains full regional rail modernization. As for the cost estimate, an independent study by researchers at Harvard’s Kennedy School of Government estimates it at about $5 billion in today’s money; the new study provides no evidence it would be higher. I urge good transit activists in Massachusetts, Rhode Island, and New Hampshire to demand better of their civil servants.

Tunneling costs

The study says that the cost of a four-track NSRL tunnel under the Big Dig would be $17 billion in 2028 dollars. In today’s money, this is $12 billion (the study assumes 3.5% annual cost escalation rather than inflation-rate cost escalation). It claims to be based on best practices, listing several comparable tunnels, both proposed and existing:

California High-Speed Rail tunnels (average estimated cost about $125 million per km, not including overheads and contingency)

Crossrail (see below on costs)

The M-30 highway tunnel in Madrid (average cost about $125 million per km of bored tunnel in the mid-2000s, or around $150 million/km in today’s money)

The canceled I-710 tunnel in California (at 7.2 km and $5.6 billion, $780 million per km

The Spoortunnel Pannerdensch Kanaal (around $200 million in today’s money for 1.6 km of bore, or $125 million per km)

Unlike the other tunnels on the list, Crossrail has stations frustrating any simple per km cost analysis. The headline cost of Crossrail is £15 billion; however, I received data from a freedom of information request showing that the central (i.e. underground) portion is only £11.6 billion and the rest is surface improvements, and of this cost the big items are £2.2 billion for tunneling, £4.1 billion for stations, £1 billion for tracks and systems, and £2.7 billion for overheads and land acquisition. The tunneling itself is thus around $150 million per km, exclusive of overheads and land (which add 30% to the rest of the project). All of this is consistent with what I’ve found in New York: tunneling is for the most part cheap.

With the exception of Crossrail, the above projects consist of two large-diameter bores. The mainline rail tunnels (California HSR and Pannerdensch Kanaal) are sized to provide plenty of free air around the train in order to improve aerodynamics, a feature that is desirable at high speed but is a luxury in a constrained, low-speed urban rail tunnel. The highway tunnels have two large-diameter bores in order to permit many lanes in each direction. The plan for NSRL has always been two 12-meter bores, allowing four tracks; at the per-km boring cost of the above projects, this 5 kilometer project should cost perhaps a billion dollars for tunneling alone.

The stations are typically the hard part. However, NSRL has always been intended to use large-diameter tunnels, which can incorporate the platforms within the bore, reducing their cost. Frequent commenter Ant6n describes how Barcelona used such a tunnel to build Metro Lines 9 and 10, going underneath the older lines; the cost of the entire project is around $170 million per km, including a cost overrun by a factor of more than 3. Vertical access is likely to be more difficult in Boston under the Big Dig than in Barcelona, but slant shafts for escalators are still possible. At the worst case scenario, Crossrail’s station costs are of an order of magnitude of many hundreds of millions of dollars each, and two especially complex ones on Crossrail 2 are £1.4 billion each; this cost may be reasonable for Central Station at Aquarium, but not at South Station or North Station, where there is room for vertical and slant shafts.

It’s possible that the study made a factor-of-two error, assuming that since the mainline rail comparison projects have two tracks, their infrastructure is sized for two urban rail tracks, where in reality a small increase in tunnel diameter would permit four.

Researchers at the Harvard Kennedy School of Government came up with an estimate of $5.9 billion in 2025 dollars for a four-track, three-station NSRL option, which is about $5 billion today. Their methodology involves looking at comparable tunneling projects around the world, and averaging several averages, one coming from American cost methodology plus 50% contingency, and two coming from looking at real-world cost ranges (one American, one incorporating American as well as rest-of-world tunnels). Their list of comparable projects includes some high-cost ones such as Second Avenue Subway, but also cheaper ones like Citybanan, which goes deep underneath Central Stockholm with mined tunnels under T-Centralen and Odenplan, at $350 million per km in today’s money.

But the MassDOT study disregarded the expertise of the Kennedy School researchers, saying,

Note: The Harvard Study did not include cost for the tunnel boring machine launch pit and only accounted for 2.7 miles of tunneling (the MassDOT studies both accounted for 5 miles of tunneling), and no contingency for risk.

This claim is fraudulent. The Kennedy School study looks at real-world costs (thus, including contingency and launch pit costs) as well as at itemized costs plus 50% contingency. Moreover, the length of the NSRL tunnel, just under 5 km, is the same either way; the MassDOT study seems to be doubling the cost because the project has four tracks, an assumption that is already taken into account in the Kennedy School study. This, again, is consistent with a factor-of-two error.

Moreover, the brazenness of the claim that a study that explicitly includes contingency does not do so suggests that MassDOT deliberately sabotaged NSRL, making it look more expensive than it is, since the top political brass does not want it. Governor Baker said NSRL looks expensive, and Secretary of Transportation Stephanie Pollack is hostile as well; most likely, facing implicit pressure from above, MassDOT’s overburdened Office of Transportation Planning scrubbed the bottom of the barrel to find evidence of absurdly high costs.

Electrification costs

Massachusetts really does not want or understand electrification. Even some NSRL supporters believe electrification to be an expensive frill that would sink the entire project and think that dual-mode locomotives are an acceptable way to run trains in a developed country in the 2010s.

In fact, dual-mode locomotives’ weak performance serves to raise tunneling costs. Struggling to accelerate at 0.3 m/s^2 (or 0.03 g), they cannot climb steep grades: both the Kennedy School and MassDOT studies assume maximum 3% grades, whereas electric multiple units, with initial acceleration of 1.2 m/s^2, can easily climb 4% and even steeper grades (in theory even 10%, in practice the highest I know of is 7%, and even 5% is rare), permitting shorter and less constrained tunnels.

As a result of its allergy to electrification, MassDOT is only proposing wiring between North Station and the next station on each of the four North Side lines, a total of 22.5 route-km. This choice of which inner segments to electrify excludes the Fairmount Line, an 8-stop 15 km mostly self-contained line through low-income, asthma-riven city neighborhoods (source, PDF-pp. 182 and 230). Even the electrification the study does agree to, consisting of about 30 km of the above surface lines plus the tunnels themselves, is projected to cost $600 million. Nowhere in the world is electrification so expensive; the only projects I know of that are even half as expensive are a pair of disasters, one coming from a botched automation attempt on the Great Western Main Line and one coming from poor industry practices on Caltrain.

A more reasonable American budget, based on Amtrak electrification costs from the 1990s, would be somewhat less than $2 billion for the entire MBTA excluding the already-wired Providence Line; this is the most familiar electrification scheme to the Bostonian reader or planner. At French or Israeli costs, the entire MBTA commuter rail system could be wired for less than a billion dollars.

Another necessary element is conversion to an all-EMU fleet, to increase performance and reduce operating costs. Railway Gazette reports that a Dutch benchmarking study found that the lifecycle costs of EMUs are half as high as those of diesel multiple units. As the MBTA needs to replace its fleet soon anyway, the incremental cost of electrification of rolling stock is negative, and yet the study tacks in $2.4 billion on top of the $17 billion for tunneling for vehicles.

A miscellany of incompetence

In addition to the sandbagged costs, the study indicates that the people involved in the process do not understand modern railroad operations in several other ways.

First, door opening. While practically everywhere else in the first world doors are automatic and opened with the push of a button, the MBTA insists on manual door opening. The MassDOT study gives no thought to high platforms and automatic doors (indeed, the Old Colony Lines are already entirely high-platform, but some of their rolling stock still employs manual door opening), and assumes manual door opening will persist even through the NSRL tunnels. Each train would need a squad of conductors to unload in Downtown Boston, and the labor costs would frustrate any attempt to run frequently (the study itself suggests hourly off-peak frequency; in Paris, RER lines run every 10-20 minutes off-peak).

Second, capacity. The study says a two-track NSRL would permit 17 trains per hour in each direction at the peak, and a four-track NSRL would permit 21. The MBTA commuter rail network is highly branched, but not more so than the Munich S-Bahn (which runs 30 at the peak on two tracks) and less so than the Zurich S-Bahn (which before the Durchmesserlinie opened ran either 20 or 24 tph through the two-track tunnel, I’m not sure which).

Worse, the FMCB itself is dumbfounded by the proposed peak frequency – in the wrong direction. While FMCB chair Joe Aiello tried explaining how modern regional rail in Tokyo works, other members didn’t get it; one member dared ask whether 17 tph is even possible on positive train control-equipped tracks. My expectations of Americans are low enough that I am not surprised they are unaware that many lines here and in Japan have automatic train protection systems (ETCS here, various flavors of ATC in Japan) that meet American PTC standards and have shorter minimum headways than every 3-4 minutes. But the North River Tunnels run 24-25 peak tph into Manhattan, using ASCES signaling, the PTC system Amtrak uses on the Northeast Corridor; the capacity problems at Penn Station are well-known to even casual observers of American infrastructure politics.

A state in which the FMCB members didn’t really get what their chair was saying about modern operations is going to propose poor operating practices going forward. MassDOT’s study assumes low frequency, and, because there is no line-wide electrification except on the Providence Line and eventually South Coast Rail (where electrification is required for wetland remediation), very low performance. MassDOT’s conception of NSRL has no infill stops, and thus no service to the bulk of the contiguous built-up area of Boston. Without electrification or high platforms, it cannot achieve high enough speeds to beat cars except in rush hour traffic. Limiting the stop penalty is paramount on urban rail, and level boarding, wide doors, and EMU acceleration combine to a stop penalty of about 55 seconds at 100 km/h and 75 seconds at 160 km/h; in contrast, the MBTA’s lumbering diesel locomotives, tugging coaches with narrow car-end doors with several steps, have a stop penalty of about 2.5 minutes at 100 km/h.

Going forward

The presentation makes it very clear what the value of MassDOT’s NSRL study is: at best none, at worst negative value through muddying the conversation with fraudulent numbers. The Office of Transportation Planning is swamped and could not produce a good study. The actual control was political: Governor Baker and Secretary of Transportation Pollack do not want NSRL, and both the private consultant that produced the study and the staff that oversaw it did what the politicians expected of them.

Heads have to roll if Massachusetts is to plan good public transportation. The most important person good transit activists should fight to remove is the governor; however, he is going to be easily reelected, and replacing the secretary of transportation with someone who does not lie to the public about costs is an uphill fight as well. Replacing incompetent civil servants elsewhere is desirable, but the fish rots from the head.

Activists in Rhode Island may have an easier time, as the state is less hostile to rail, despite the flop of Wickford Junction; they may wish to demand the state take lead on improving service levels on the Providence Line, with an eye toward forcing future NSRL plans to incorporate good regional rail practices. In New Hampshire, provided the state government became less hostile to public investment, activists could likewise demand high-quality commuter rail service, with an eye toward later connecting a North Station-Nashua-Manchester line to the South Side lines.

But no matter what, good transit activists cannot take the study seriously as a planning study. It is a political document, designed to sandbag a rail project that has high costs and even higher benefits that the governor does not wish to manage. Its cost estimates are not only outlandish but brazenly so, and its insistence that the Kennedy School study does not include contingency is so obviously incorrect that it must be considered fraud rather than a mistake. Nothing it says has any merit, not should it be taken seriously. It does not represent the world of transportation planning, but rather the fantasies of a political system that does not understand public transportation.