I’ve been thinking about MBTA modernization recently, and realized that although the principles underlying modernization are similar throughout North America, the concrete benefits and the resulting political alliances that could push for it are very different. In New York and Chicago, commuter rail is already quite good if you’re a suburban middle-class commuter working in the CBD at regular business hours. Penn Station may not be ideally located for Midtown commuters, but the LIRR is building East Side Access to fix that; this leads to arguments such as this one, about which group of riders (or potential) riders to prioritize.
The MBTA is completely different. It does not provide adequate service even for peak-hour commuters, because the speed leaves a lot to be desired; where the LIRR runs decent if not good rolling stock, the MBTA rolling stock loses 70 seconds accelerating just to 60 mph (FLIRTs lost 24 seconds accelerating to 160 km/h). As Purple City notes in comments, electrification would be a Pareto-improvement, allowing large increases in speed even with infill stops. The discussion of whether to prioritize short-distance or long-distance service is still important, but any choice would substantially improve service to everyone over the current offering.
This means that the politics of modernization is different. In New York, Long Island commuters are the primary obstacle: modernization would replace their peak express trains with reverse-peak trains on the one-way Main Line, and crowd their trains in the outbound direction. In Boston, there aren’t enough urban riders to result in so much crowding, the speed would go up substantially, and, with the North-South Rail Link, North Side commuters would have service to the CBD and not just North Station.
The cost of such modernization consists of four main projects: the North-South Rail Link itself, complete electrification of all lines, full-length high platforms at all stations, and new rolling stock. The latter is perhaps $1.5 billion initially, corresponding to 600 cars, but in reality displaces equivalent or higher cost that has to be spent on new diesel locomotives and cars under the current operating pattern. The NSRL was pegged at $3-4 billion, but since it’s in easy geology (the ground was already cleared during the Big Dig), costs do not have to be higher than in the rest of the world, which would be closer to $2 billion for two large-diameter bores. Complete electrification is perhaps another $1.5 billion. It’s a fraction of what the state spent on the Big Dig, and not a large multiple of what it’s spending on a few thousand daily riders for South Coast Rail.
The political alliance in this case would be the exact one that would oppose modernization in New York and Chicago. This list of projects does little for the inner city, with exceptions around possible infill station sites like Allston. However, it provides much higher speeds for the suburbs. This is what’s so interesting about it. It’s not even easy to unbundle the parts that are useful to the suburbs from the parts that improve service in general, since the North-South Rail Link, which is crucial for service from the north to Boston, requires electrification, and once that’s in place, high platforms and infill stations are cheap. Whereas elsewhere, political inertia makes modernization hard, in the Boston area, once someone proposes it, I believe large chunks of the mainstream will jump on the idea.