After drawing a map of an integrated timed transfer intercity rail network for the state of New York, people asked me to do other parts of the United States. Here is New England, with trains running every 30 minutes between major cities:

New England is a much friendlier environment for intercity rail growth than Upstate New York, but planning there is much more delicate. The map thus has unavoidable omissions and judgment calls, unlike the New York map, which straightforwardly follows the rule of depicting intercity lines but not suburban lines like the Long Island network. I ask that people not flame me about why I included X but not Y without reading the following explanations.

The tension between S-Bahn and ITT planning

The S-Bahn concept involves interlining suburban rail lines through city center to provide a high-frequency urban trunk line. For example, trains from a number of East Berlin neighborhoods and Brandenburg suburbs interline to form the Stadtbahn: in the suburbs, they run every 10 or 20 minutes, but within the Ring, they combine to form a diameter running regularly every 3:20 minutes.

The integrated transfer timetable concept instead involves connecting different nodes at regular intervals, typically half an hour or an hour, such that trains arrive at every node just before a common time and leave just after, to allow people to transfer. In a number of major Swiss cities, intercity trains arrive a few minutes before the hour every 30 minutes and depart a few minutes after, so that people can connect in a short amount of time.

S-Bahn and ITT planning are both crucial tools for good rail service, but they conflict in major cities. The ITT requires all trains to arrive in a city around the same time, and depart a few minutes later. This forces trains from different cities to have different approach tracks; if they share a trunk, they can still arrive spaced 2-3 minutes apart, but this lengthens the transfer window. The idea of an S-Bahn trunk involves trains serving the trunk evenly, which is not how one runs an ITT.

Normally, this is no problem – ITTs are for intercity trains, S-Bahns are for local service. But this becomes a problem if a city is so big that its S-Bahn network grows to encompass nearby city centers. In New York, the city is so big that its shadow reaches as far as Eastern Long Island, New Haven, Poughkeepsie, and Trenton. Boston is smaller but still casts shadows as far as southern New Hampshire and Cape Cod.

This is why I don’t depict anything on Long Island on my map: it has to be treated as the extension of an S-Bahn system, and cannot be the priority for any intercity ITT. This is also true of Danbury and Waterbury: both are excellent outer ends for an electrified half-hourly regional rail system, but setting up the timed transfers with the New Haven Line (which should be running every 10 minutes) and with high-speed rail (which has no reason to stop at the branch points with either Danbury or Waterbury) is infeasible. In Boston I do depict some lines – see below on the complications of the North-South Rail Link.

The issue of NSRL

The North-South Rail Link is a proposed north-south regional rail tunnel connecting Boston’s North and South Stations. Current plans call for a four-track tunnel extending across the river just north of North Station, about 4.5 km of route; it should cost $4 billion including stations, but Massachusetts is so intent on not building it lies that the cost is $12 billion in 2018 dollars.

In common American fashion, NSRL plans are vague about how service is to run through the tunnel. There are some promises of running intercity trains in addition to regional ones; Amtrak has expressed some interest in running trains through from the Northeast Corridor up to the northern suburbs and thence to Maine. However, we are not engaging in bad American planning for the purposes of this post, but in good Central European planning, and thus we must talk about what trains should run and design the tunnel appropriately.

The rub is that Boston’s location makes NSRL great for local traffic and terrible for intercity traffic. When it comes to local traffic, Boston is right in the middle of its metropolitan region, just offset to the east because of the coast. The populations of the North Side and South Side suburbs are fairly close, as are their commuter volumes into Boston. Current commuter rail ridership is about twice as high on the South Side, but that’s because South Station’s location is more central than North Station’s. NSRL really is a perfect S-Bahn trunk tunnel.

But when it comes to intercity traffic, Boston is in the northeast corner of the United States. There are no major cities north of Boston – the largest such city, Portland, is a metro area of 600,000. In contrast, going south, New York should not be much more than an hour and a half away by high-speed rail. Thus, high-speed rail has no business running through north of Boston – the demand mismatch south and north is too high.

Since NSRL is greatly useful for regional traffic but not intercity traffic, the physical infrastructure should be based on S-Bahn and not ITT principles, even though the regional network connects cities quite far away. For one, the tunnel should require all trains to make all stops (South Station, Aquarium, North Station) for maximum local connectivity. High-speed trains can keep feeding South Station on the surface, while all other traffic uses the tunnel.

But on the North Side, feeding North Station on the surface is not a good idea for intercity trains. The station is still awkwardly just outside city center. It also offers no opportunity to transfer to intercity trains to the most important city of all, New York.

The only resolution is to treat trains to Portland and New Hampshire as regional trains that just go farther than normal. The Nashua-Manchester-Concord corridor is already as economically linked to Boston as Providence and Worcester, and there are plans for commuter rail service there already, which were delayed due to political opposition to spending money on trains from New Hampshire Republicans after their 2010 election victory. Portland is more speculative, but electric trains could connect it with Boston in around an hour and a half to two hours. These trains would be making suburban stops north of Boston that an intercity train shouldn’t normally make, but it’s fine, the Lowell Line has wide stop spacing and the intermediate stops are pretty important post-industrial cities. At Portland, passengers can make a timed connection to trains to Bangor, on the same schedule but with shorter trainsets as the demand north of Portland is much weaker.

On the map, I also depict Boston-Cape Cod trains, which like Boston-Concord trains are really suburban trains but going farther. Potentially, the branch to Cape Cod – the Middleborough branch of the Old Colony Lines – could even run through with the Lowell Line, either the branch to Concord or the Wildcat Branch to Haverhill and Portland. Moreover, the sequencing of the branches should aim to give short connections to Boston-Albany high-speed trains as far as reasonable.

The issue of the Northeast Corridor

The Northeast Corridor wrecks the ITT plan in two ways, one substantial and one graphical.

The snag is that there should be service on legacy track running at a maximum speed of 160-200 km/h in addition to high-speed service on high-speed tracks. There may be some track sharing between New York and New Haven to reduce construction costs, using timed overtakes instead of full track segregation, but east of New Haven the high-speed trains should run on a new line near I-95 to bypass the Shore Line’s curves, and the Shore Line should be running electric regional trains to connect to the intermediate cities.

The graphical problem is that the distance between where the legacy route is and where the high-speed tracks should be is short, especially west of New Haven, and depicting a red line and a blue line together on the map is not easy. I will eventually post something at much higher resolution than 1 pixel = 500 meters. This also affects long-distance regional lines that I’d like to depict on the map but connect only to legacy trains on the Northeast Corridor, that is the Danbury and Waterbury Branches.

For planning purposes, figure that both run every half hour all day, are electric, run through to and beyond New York as branches of the New Haven Line, and are timed to have reasonable connections to high-speed trains to Albany and points north in New York. Figure the same for trains between New Haven and Providence, with some additional runs in the Providence suburbs giving 15-minute urban frequencies to such destinations as Olneyville and Cranston.

The substantial issue is that the Northeast Corridor is far too high-demand for a half-hourly ITT. Intercity trains run between New York and Boston better than hourly today, and that’s taking twice as long as a TGV and charging 2.5-4 times as much. My unspoken assumption when planning how everything should fit together is that there should be a 400-meter long train every 15 minutes on the corridor past New Haven, spaced evenly around Boston to overtake regional trains to Providence at consistent locations. Potentially, there should be more local trains taking around 1:50 and more express trains taking around 1:35, and then all timed transfers should be to the local trains.

On the New Haven Line, too, regional rail demand is much more than a train every half hour. Trains run mostly every half hour today, with management that is flagrantly indifferent to off-peak service, and trip times that are about 50% longer than they should be. Nonetheless, best practice is to set up timed transfers such that various branches all connect to the same train, so that passengers can connect between different branches. This mostly affects Waterbury; it’s useful to ensure that Waterbury trains arrive at Bridgeport with a short transfer to a train toward New Haven that offers a quick connection to trains to points north and east.

Planning HSR around timed connections

Not counting lines that are in the Boston sphere, or the lines around Albany, which I discussed two weeks ago, there are three lines proposed for timed connection to high-speed rail: New London-Norwich, Providence-Worcester-Fitchburg, Springfield-Greenfield.

All three are regional lines, not intercity lines. They are not optimized for intercity speed, but instead make a number of local urban and suburban stops. This is especially true of Springfield-Northampton-Greenfield, a line that Sandy Johnston and I have been talking about since 2014. A Springfield-Greenfield line with 1-2 intermediate stops might be able to do a one-way trip in around 39 minutes, at which point a 45-minute operator schedule may be feasible with a very tight turnaround regime – but there’s enough urban demand along the southern half of the route that adding stops to make it about 50 minutes with a one-hour operator schedule is better.

The Providence-Worcester line is likewise slower than it could be if it were just about Providence and Worcester. The reason is that high-speed rail compresses distances along its route. Providence-Boston by high-speed rail is about 22 minutes nonstop, including schedule contingency. Boston-Worcester is about the same – slower near Boston because of scheduling difficulties along the Turnpike and the inner Worcester Line, faster near the outer end because Worcester has no chance of getting a city center station but rather gets a highway station. Now, passengers have a range of transfer penalties, and to those who are averse to connections and have a high personal penalty, the trip between the two cities is more attractive directly than via Boston. But there are enough passengers who’d make the trip via Boston that the relative importance of intermediate points grows: Pawtucket, Woonsocket, Uxbridge, Millbury. In that situation, the importance of frequency grows (half-hourly is a must, not hourly) and that of raw speed diminishes.

The onward connection to Fitchburg is about three things. First, connecting Providence with Fitchburg. Second, connecting Worcester with Fitchburg. And third, connecting Fitchburg with the high-speed line. This makes investments into higher speed more valuable, since Fitchburg’s importance is high compared with that of points between Worcester and Fitchburg. The transfer between the line and high-speed rail should be timed in the direction of Fitchburg-to-Albany first of all, and Providence-to-Albany second of all, as the connections from the endpoints to Boston are slower than direct commuter trains.

The presence of this connection also forces the Worcester station to be at the intersection with the line to Providence. Without this connection, it may be better to site the station slightly to the west, at 290 rather than 146, as the area already has Auburn Mall.

Finally, the New London-Norwich line is a pure last-mile connector from the New London train station, which is forced to be right underneath the I-95 bridge over the river, to destinations to the north. The northern anchor is Norwich opposite the historic center, but the main destination is probably the Mohegan Sun casino complex. Already there are many buses connecting passengers from New York to the casino. The one-way trip time should be on the order of 21-22 minutes, but with a turnaround it’s a 30-minute schedule, and the extension south to the historic center of New London is for completeness; with a timed connection, trains could get between Penn Station and Norwich in around 1:20 counting connection time, and between Penn Station and Mohegan Sun in maybe 5 minutes less.

What about Vermont?

Vermont’s situation is awkward. Burlington is too far north and too small to justify a connection to high-speed rail by itself. A low-speed connection might work, but the line from Burlington south points toward Rutland and not New York, and connecting it onward requires reversing direction. If Vermont had twice its actual population this might be viable, but it doesn’t.

But Vermont is right between New York and Montreal. I generally don’t show New York-Montreal high-speed rail on my maps. It’s a viable line, but people in both cities severely overrate it, especially compared with New York-Toronto; I have to remind readers this whenever I write about international high-speed trains. In the event such a line does open, Burlington is the only plausible location for a Vermont stop – everything else is too small, even towns that historically did have rail service, like Middlebury. Rutland could get a line running partly on high-speed track and partly on legacy track taking it down to Glens Falls or Saratoga Springs to transfer to onward destinations, or maybe Albany if trains run 2-3 minutes apart in pairs every 30 minutes.

Current plans for Vermont try to connect it directly to Boston via New Hampshire, and that is wrong. The Vermonter route is mountainous from Greenfield to Burlington; trains will never be competitive with driving there. Another route under occasional study going into Boston from the north was even included on a 2009 wishlist of high-speed rail routes, under the traditional American definition of high-speed rail as “train that is faster than a sports bicycle.” That route, crossing mountains in both New Hampshire and Vermont, is even worse. The north-south orientation of the mountains in both states forces east-west routes to either stick to the lowlands or consolidate to strong enough routes that high-speed rail tunnels are worthwhile.

How much does this cost?

As always, I am going to completely omit the Northeast Corridor from this cost analysis; an analysis of that will happen later, and suffice is to say, the benefit-cost ratio if there’s even semi-decent cost control is extremely high.

With that in mind, the central pieces of this program are high-speed lines from Boston to Albany and from New Haven to Springfield, in a T system. The 99 km New Haven-Springfield line, timetabled at 45 minutes including turnaround and maybe 36 minutes in motion, is on the slow side for high-speed rail, as it is short and has a crucial intermediate station in Hartford. It does not need any tunnels or complex viaducts, and property takings are nonzero but light; the cost should not be higher than about $2-2.5 billion, utilizing legacy track for much of the way.

The Boston-Albany line is much costlier. It’s 260 km, and crosses the aforementioned north-south mountains in Western Massachusetts. Tunnels are unavoidable, including a few kilometers of digging required just west of Springfield to avoid a slowdown on suburban curves. At the Boston end, tunneling may also be unavoidable next to the Turnpike. The alternative is sharing a two-track narrows with the MBTA Worcester Line in Newton; it’s possible if the trains run no more than every 15 minutes, which is a reasonable short-term imposition but may be too onerous in the longer term if better service builds up more demand for commuter rail frequency in Newton. My best guess is that without Newton, the line needs around 20 km of tunnel and can piggyback on 35 km of existing lines at both ends, for a total cost in the $6-8 billion range. This figure is sensitive to whether my 20 km estimate is correct, but not too sensitive – at 40 it grows to maybe $9 billion, at 0 it shrinks to $4.5 billion.

Estimating the costs of the blue lines on the map is harder. All of them are, by the standard of high-speed rail, very cheap per kilometer. A track renewal machine on a one-third-in-tunnel German high-speed line can do track rebuilding for about a million euros per single-track-kilometer. All of these lines would also need to be electrified from scratch, for $1.5-3 million per kilometer. Stations would need to be built, for a few million apiece. My first-order estimate is $1 billion for the three blue connector lines and about the same for Boston-Portland-Bangor; the Hyannis and Concord lines would go in a regional rail basket. The NSRL tunnel should be $4 billion or not much more, and not what Massachusetts wants voters to believe it is to justify its decision not to build it.

The reason for the relatively limited map (e.g. no Montreal service) is that these lines are not such slam dunks that they’re worth it at any price. Cost control is paramount, subject to the bare minimum of good service (e.g. electrification and level boarding). For what I think a fair cost is, those lines are still good, providing fast connectivity across New England from most places to most other places. Moreover, the locations of the major nodes, like Worcester and Springfield, allow timing bus interchanges as well, providing further connections to various suburbs and city neighborhoods.

The red high-speed lines are flashy, but the blue ones are important too. That’s the key takeaway from planning in Switzerland, Austria, and the Netherlands, all of which have high rail usage without great geography for intercity rail. Trains should be planned coherently as a network, with all parts designed in tandem to maximize connectivity. This isn’t just about going between Boston and Springfield or Boston and Albany or New Haven and Springfield, but also the long tail of weaker markets using timed connections, like New Haven-Amherst, Brockton-Worcester, Dover-Providence, Stamford-Mohegan Sun, and so on. A robust rail network based on ITT design principles could make all of these and many more connections at reasonable cost and speed.