I refined my train performance calculator to automatically compute trip times from speed zones. Open it in Python 3 IDLE and play with the functions for speed zones – so far it can’t input stations, only speed zones on running track, with stations assumed at the beginning and end of the line.
I’ve applied this to a Northeast Corridor alignment between New York and Boston. The technical trip times based on the code and the alignment I drew are 0:36:21 New York-New Haven, 0:34:17 New Haven-Providence, 0:20:40 Providence-Boston; with 1-minute dwell times, this is 1:33 New York-Boston, rising to maybe 1:40 with schedule contingency. This is noticeably longer than I got in previous attempts to draw alignments, where I had around 1:28 without pad or 1:35 with; the difference is mainly in New York State, where I am less aggressive about rebuilding entire curves than I was before.
I’m not uploading this alignment yet because I want to fiddle with some 10 meter-scale questions. The most difficult part of this is between New Rochelle and New Haven. Demolitions of high-price residential properties are unavoidable, especially in Darien, where there is no alternative to carving a new right-of-way through Noroton Heights.
The importance of speeding up the slowest segments
The above trip times are computed based on the assumption that trains depart Penn Station at 60 km/h as they go through the interlocking, and then speed up to 160 km/h across the East River, using the aerodynamic noses designed for 360 km/h to achieve medium speed through tunnels with very little free air. This require redoing the switches at the interlocking; this is fine, switches in the United States are literally 19th-century technology, and upgrading them to Germany’s 1925 technology would create extra speed on the slowest segment.
Another important place to speed up is Shell Interlocking. The current version of the alignment shaves it completely, demolishing some low-rise commercial property in the process, to allow for 220 km/h speeds through the city. Grade separation is obligatory – the interlocking today is at-grade, which imposes unreasonable dependency between northbound and southbound schedules on a busy commuter railroad (about 20 Metro-North trains per hour in the peak direction).
In general, bypasses west of New Haven prioritize the slowest segments of the Northeast Corridor: the curves around the New York/Connecticut state line, Darien, Bridgeport. East of New Haven the entire line should be bypassed until Kingston, even the somewhat less curvy segment between East Haven and Old Saybrook, just because it’s a relatively easy segment where the railroad can mostly twin with I-95 and not have any complex viaducts.
The maximum speed is set at 360 km/h, but even though trains can cruise at such speed on two segments totaling 130 km, the difference in trip time with 300 km/h is only about 3 minutes. Similarly, in southwestern Connecticut, the maximum speed on parts of the line, mostly bypasses, is 250 km/h, and if trains could run at 280 km/h on those segments, which isn’t even always possible given curvature, it would save just 1 minute. The big savings come from turning a 10 miles per hour interlocking into a modern 60 km/h (or, ideally, 90+ km/h) one, eliminating the blanket 120 km/h speed limit between the NY/CT state line and New Haven, and speeding up throats around intermediate stations.
Bypasses are easier to draw than curve modifications. Curves on the Northeast Corridor don’t always have consistent radii – for example, the curves flanking Pawtucket look like they have radius 600 meters, but no, they have a few radii of which the tightest are about 400 meters, constraining speed further. Modifying such curves mostly within right-of-way should be a priority.
Going outside the right-of-way is also plausible, at a few locations. The area just west of Green’s Farms is a good candidate; so is Boston Switch, a tight curve somewhat northeast of Pawtucket whose inside is mostly water. A few more speculative places could get some noticeable trip time improvements, especially in the Bronx, but the benefit-cost ratio is unlikely to be good.
Bush consulting on takings
In some situations, there’s a choice of which route to take – for example, which side of I-95 to go on east of New Haven (my alignment mostly stays on the north side). Some right-of-way deviations from I-95 offer additional choice about what to demolish in the way.
In that case, it’s useful to look for less valuable commercial properties, and try to avoid extensive residential takings if it’s possible (and often it isn’t). This leads to some bush consulting estimates of how valuable a strip mall or hotel or bank branch is. It’s especially valuable when there are many options, because then it’s harder for one holdout to demand unreasonable compensation or make political threats – the railroad can go around them and pay slightly more for an easier takings process.
How fast should trains run?
Swiss planners run trains as fast as necessary, not as fast as possible. This plan does the opposite, first in order to establish a baseline for what can be done on a significant but not insane budget, and second because the expected frequency is high enough that hourly knots are not really feasible.
At most, some local high-speed trains could be designated as knot trains, reaching major stations on the hour or half-hour for regional train connections to inland cities. For example, such a local train could do New York-Boston in 2 hours rather than 1:40, with such additional stops as New Rochelle, Stamford, New London (at I-95, slightly north of the current stop), and Route 128 or Back Bay.
But for the most part, the regional rail connections are minor. New York and Boston are both huge cities, so a train that connects them in 1:40 is mostly an end-to-end train, beefed up by onward connections to Philadelphia, Baltimore, and Washington. Intermediate stops at New Haven and Providence supply some ridership too, much more so than any outlying regional connections like Danbury and Westerly, first because those outlying regional connections are much smaller towns and second much of the trip to those towns is at low speed so the trip time is not as convenient as on an all-high-speed route.
This does not mean Swiss planning maxims can be abandoned. Internal traffic in New England, or in Pennsylvania and South Jersey, or other such regions outside the immediate suburbs of big cities, must hew to these principles. Even big-city regional trains often have tails where half-hourly frequency is all that is justified. However, the high-speed line between Boston and New York (and Washington) specifically should run fast and rely on trips between the big cities to fill trains.
How much does it cost?
My estimate remains unchanged – maybe $7 billion in infrastructure costs, closer to $9-10 billion with rolling stock. Only one tunnel is included, under Bridgeport; everywhere else I’ve made an effort to use viaducts and commercial takings to avoid tunneling to limit costs. The 120 km of greenfield track between New Haven and Kingston include three major viaducts, crossing the Quinnipiac, Connecticut, and Thames; otherwise there are barely any environmentally or topographically sensitive areas and not many areas with delicate balance of eminent domain versus civil infrastructure.
I repeat, in case it is somehow unclear: for $7 billion in infrastructure investment, maybe $8 billion in year-of-expenditure dollars deflated to the early 2020s rather than early 2010s, trains could connect New York and Boston in 1:40. A similar project producing similar trip times between New York and Washington should cost less, my guess is around $3 billion, consisting mostly of resurrecting the old two-track B&P replacement in lieu of the current scope creep hell, building a few at-grade bypasses in Delaware and Maryland, and replacing the variable-tension catenary with constant-tension catenary.
None of this has to be expensive. Other parts of the world profitably build high-speed rail between cities of which the largest is about the size of Boston or Philadelphia rather than the smallest; Sweden is seriously thinking about high-speed trains between cities all of which combined still have fewer people than metropolitan Boston. Better things are possible, on a budget, and not just in theory – it’s demonstrated every few years when a new high-speed rail line opens in a medium-size European or Asian country.