The great missing piece of New York’s rail network, and the most controversial of any of my proposals, is Staten Island. Connected to New Jersey by the B&O but not toward Manhattan, it relies on buses to the subway and the ferry for its connection to jobs in the rest of New York. Unsurprisingly, this is too slow and low-capacity for the full benefit of rapid transit to emerge, and the borough’s character remains suburban.
Plenty of railfans and transit supporters believe that the subway should be extended from Bay Ridge to Staten Island across the Narrows; the Fourth Avenue Line contains some landside infrastructure preparing for such an extension. While this is one of the options that should be studied, it suffers in two ways: first, the Narrows are the deepest part of New York Harbor, at about 25 meters (83 ft.), and second, the Staten Island end would be at Grasmere, a low-density area.
In contrast, according to the nautical chart, paths that go from St. George to any point between Manhattan and the Bay Ridge freight terminal are at the deepest 16 meters (53 ft.) below mean low water. In addition, the North Shore is the densest and most densifiable part of the borough, and would get better service; the South Shore would get about the same amount of service no matter where east of the Narrows the tunnel landed, but is the less important part of the borough to connect.
I contend that the list of options is as depicted on this map. The main choice is between a direct route and a route that goes through Brooklyn, trading off speed versus intermediate stops and possibly cost. Observe that it is much easier for a line that detours through Brooklyn to serve Downtown Brooklyn at Borough Hall than at the existing train station; this provides some justification for adding a Borough Hall station to a New Jersey-Brooklyn regional rail tunnel.
Not depicted on the map is the interaction of the various alignments with Harbor geology. If the primary factor is minimizing tunnel depth, then there are two options, one more easterly, near or under Governor’s Island or even farther east, and one more westerly, near the mouth of the Hudson. The westerly option opens the possibility for an east-west alignment through Manhattan that goes the “wrong way” – that is, has the Uptown direction pointing in the same direction as the Brooklyn-bound direction of the New Jersey-Brooklyn tunnel. This would give a cross-platform transfer from Staten Island to Brooklyn, which is lacking from the standard direct option.
Another issue is a South Ferry stop. As discussed in my post about the Lower Manhattan station siting, a South Ferry station becomes necessary if the main Lower Manhattan station is too far north, roughly north of Fulton Street. Even if the station is at or marginally south of Fulton, a second Lower Manhattan station could help reduce dwell times at the main station, increasing capacity.
A related issue is keeping all traffic that doesn’t need to be in Manhattan out of the main station. The Staten Island-Brooklyn transfer hogs passenger circulation space. It’s bad enough that a greenfield 100 km/h regional rail tunnel would get people from Atlantic/Pacific to Grand Central in about 11 minutes plus transfer time, versus about 20 on the 4/5, which make more or less the same stops, adding cross-platform transfers. A relief station at South Ferry, or Borough Hall, would go a long way toward mitigating this. (Observe that in the service patterns I’ve proposed for the lines that converge on Midtown, the main transfer points are Secaucus and Sunnyside, avoiding Penn Station.)
For the options that detour through Brooklyn, the choice of neighborhoods to serve and the choice of how much land versus sea tunneling both give rise to several options. One option would serve Red Hook, connecting it either directly to Manhattan or via Borough Hall, giving it a rapid transit connection it currently lacks. Offering new rapid transit service to neighborhoods that lack it is always a positive, and could also get very good ridership: for a similar example, the MTA’s ridership model for New Rochelle-Penn Station commuter rail service was bullish about the potential of a Co-op City station.
A separate choice is regional rail versus subway. A subway alignment’s main advantage is that it requires less tunneling, just enough to hook the Staten Island Railway into the Fourth Avenue Line. The main disadvantages are that it’s slower than express regional rail, and that the southern Brooklyn subways already suffer from excessive branching and middling frequency.
From the start, the BMT had a problem with merging eight tracks to six, with suboptimal junctions. The Chrystie Street Connection did not change this – it merely allowed all six tracks (the four Broadway Line tracks and the two express Sixth Avenue Line tracks) to serve Midtown. On top of this, Manhattan-Coney Island is not as thick a market as it used to be; with today’s usage patterns, nobody would think to build four different routes to Coney Island plus one to Bay Ridge while leaving Utica unserved and Nostrand a short stub. Additional branching would cut into the frequency of existing lines, worsening service to existing middle-density neighborhoods in southern Brooklyn. Thus, a regional rail option, if it’s at all affordable, would provide much better service. Even the option of connecting the new line to the 59th Street station in Sunset Park would be preserved if the line followed the Gowanus Expressway.
For a few numbers: the proposed cost of the Cross-Harbor Tunnel is $7.4 billion for the double-tracked option; the length and geology are comparable to Staten Island-Manhattan. As of 2000, the total commute market from Staten Island to Manhattan is 53,000 people, i.e. 106,000 trips; additional travel to Brooklyn is 29,000 people, and travel to points north and east of Manhattan is 8,000. Cutting one to two transfers and about twenty minutes from each one-way trip could ensure nearly 100% mode share for travel to Manhattan, as well as a significant mode share to other parts of the city.
Moreover, a zoning deal raising density in St. George and right next to the train station could raise the size of the commute market, adding to ridership. While Staten Island is not particularly pro-development, and has engaged in downzoning recently, a deal in which Staten Islanders get their commute improved so much in exchange for accepting change to their neighborhood could be acceptable. Tellingly, for the North Shore Branch reactivation, the people near the line seem more interested in the higher-intensity options: rail over bus, and possibly heavy rail rather than light rail. NIMBY attitudes are reduced when the change in question is bundled with solving a known local problem, in this case very long commutes.