The simplest train schedules are when every train makes every stop. This means there are no required overtakes, and no need for elaborate track construction except for reasons of capacity. In nearly all cities in the world, double-track mainlines with flying junctions for branches are enough for regional rail. Schedule complexity comes from branching and short-turns, and from the decision which lines to join together, but it’s then possible to run independently-scheduled lines, in which delays don’t propagate. I have worked on a map as part of a proposal for Boston, and there, the only real difficulty is how to optimize turnaround times..
But then there’s New York. New York is big enough that some trunk lines have and need four tracks, introducing local and express patterns. It also has reverse-branching on some lines: the Hudson Line and New Haven Line can serve either Penn Station or Grand Central, and there are key urban stations on the connections from either station to either line. The presence of Jamaica Station makes it tempting to reverse-branch the LIRR. Everything together makes for a complex map. I talked in 2014 about a five- or six-line system, and even there, without the local/express artifacts, the map looks complicated. Key decisions turn out to depend on rolling stock, on scheduling, and on decisions made about intercity rail fares.
Here is what I drew last week. It’s a six-line map: lines 1 and 2 connect the Northeast Corridor on both sides plus logical branches and the Port Washington Branch of the LIRR, line 3 connects Hempstead with the Empire Corridor, line 4 connects the Harlem Line with the Staten Island Railway as a north-south trunk, line 5 connects the Erie Lines with the South Side LIRR lines, line 6 connects the Morris and Essex Lines with the LIRR Main Line.
As I indicated in the map’s text, there are extra possible lines, going up to 9; if I revised the map to include one line, call it line 7, I’d connect the Northern Branch and West Shore Railroad to a separate tunnel under 43rd Street, going east and taking over the LIRR portions of line 3; then the new line 3 would connect the Hudson Line with the Montauk Line (both Lower Montauk and the Babylon Branch) via an East River Tunnel extension. The other options are at this point too speculative even for me; I’m not even certain about line 6, let alone line 7, let alone anything else.
But the real difficulty isn’t how to add lines, if at all. It’s the reverse branch of lines 1 and 2. These two lines mostly go together in New Jersey and on the New Haven Line, but then take two different routes to Manhattan. The difficulty is how to assign local and express trains. The map has all line 1 trains going local: New Brunswick-Port Washington, or Long Branch-Stamford. Line 2 trains are a mix of local and express. This is a difficult decision, and I don’t know that this is the right choice. Several different scheduling constraints exist:
- Intercity trains should use line 1 and not line 2. This is for two reasons: the curve radius between Penn Station and Grand Central might be too tight for Shinkansen trains; and the Metro-North trunk north of Grand Central has no room for extra tracks, so that the speed difference between intercity and regional trains (e.g. no stop at Harlem-125th) would limit capacity. For the same reason, line 1 only has a peak of 6 trains per hour on the Northeast Corridor east of where the Port Washington Branch splits.
- Since not many regional trains can go between New Rochelle and Penn Station on the Northeast Corridor, they should provide local service – express service should all go via Grand Central.
- There are long segments with only four tracks, requiring track sharing between intercity trains and express regional trains. These occur between New Rochelle and Rye, and between the end of six-tracking in Rahway and New Brunswick. See details and a sample schedule without new Hudson tunnels here. This encourages breaking service so that in the Manhattan core, it’s the local trains that share tunnel tracks with intercity trains, while express trains, which share tracks farther out, are less constrained.
- Express trains on the New Jersey side should stay express on the New Haven Line, to provide fast service on some plausible station pairs like Newark-Stamford or New Rochelle-New Brunswick. Flipping local and express service through Manhattan means through-riders would have to transfer at Secaucus (which is plausible) or Penn Station (which is a bad idea no matter how the station is configured).
- There should be infill stops in Hudson County: at Bergenline Avenue for bus connections and the high local population density, and just outside the portal, at the intersection with the Northern Branch. These stops should be on line 2 (where they can be built new) and not line 1 (where the tunnels would need to be retrofitted), and trains cannot skip them, so the line that gets these stops should run locals.
It is not possible to satisfy all constraints simultaneously. Constraint 5 means that in New Jersey, line 2 should be local and line 1 should be express. Constraint 4 means the same should be true on the Metro-North side. But then constraints 2 and 3 encourage making line 1 local, especially on the Metro-North side. Something has to give.
On the map, the compromise is that there’s an infill stop at Bergenline but not at the intersection with the Northern Branch (which further encourages detaching the Northern Branch from line 5 and making it part of a Midtown-serving line 7). So the line 2 express trains are one stop slower than the line 1 locals between Newark and New York, which is not a huge problem.
The scheduling is still a problem, The four-track segment through Elizabeth between the six-track segments around Newark Airport and in Linden and Rahway has to be widened to six tracks; the four-track segment between the split with the North Jersey Coast Line and Jersey Avenue can mix three speed classes, with some express trains sharing tracks with intercity trains and others with local trains, but it’s not easy. At least on the Connecticut side, any high-speed rail service requires so many bypasses along I-95 that those bypasses can be used for overtakes.
At this point, it stops being purely about regional rail scheduling. The question of intercity rail fares becomes relevant: can people take intercity trains within the metro area with no or limited surcharge over regional trains? If so, then constraint 4 is no longer relevant: nobody would take regional trains on any segment served by intercity trains. In turn, there would be demand for local intercity trains, stopping not just at New Haven, New York, Newark, and Philadelphia, but also at Stamford, New Rochelle, perhaps Metropark (on new express platforms), and Trenton. In that case, the simplest solution is to flip lines 1 and 2 in New Jersey: line 1 gets the express trains to Trenton and the trains going all the way to Bay Head, line 2 gets the locals to Jersey Avenue, the Raritan Valley Line trains, and the Long Branch short-turns.
This, in turn, depends on rolling stock. Non-tilting high-speed trains could easily permit passengers with unreserved seats to pay commuter rail fare. On tilting trains, this is dicier. In Germany, tilting trains with unreserved tickets (ICE-T) have a computer constantly checking whether the train is light enough to be allowed to tilt, and if it is too heavy, it shuts down the tilt mechanism. This should not be acceptable for the Northeast Corridor. This might not be necessary for tilting Shinkansen (which are so light to begin with this isn’t a problem, and they do sell unreserved tickets in Japan), but it’s necessary for Pendolinos and for the Avelias that Amtrak just ordered. Selling reserved tickets at commuter rail fares is another option, but it might not be plausible given peak demand into New York.
The point of this exercise is that the best transit planning requires integrating all aspects: rolling stock, timetable, infrastructure, and even pricing. Questions like “can intercity trains charge people commuter rail fares for unreserved tickets?” affect express regional service, which in turn affects which branch connects to which trunk line.
Ultimately, this is the reason I draw expansive maps like this one. Piecemeal planning, line by line, leads to kludges, which are rarely optimized for interconnected service. New York is full of examples of poor planning coming from disintegrated planning, especially on Long Island. I contend that the fact that, for all of the Gateway project’s scope creep and cost escalations, there’s no proposed stop at Bergenline Avenue, is a prime example of this planning by kludge. To build the optimal line 2, the region really needs to know where lines 3-6 should go, and right now, there’s simply none of this long-term planning.