Stephen J Smith has a piece up at the New York Observer on how much capacity can be squeezed out of New York’s L line (14th St-Canarsie), in relation to a massive proposed development in Williamsburg. The answer seems to be “a lot”, and Smith does an excellent job in showing his work. A combination of signals upgrades and power system upgrades can yield a 38% increase in the available capacity of the notoriously crowded two-track line (in trains per hour); while new rolling stock, and new development patterns permitted on the streets above the subway in Brooklyn, can balance the loading profile of the trains and make that capacity more productive. It’s a good case study in how to get maximum leverage out of existing infrastructure. Important in New York, where resources are strained by a cost structure resulting in $1 billion/km subway construction costs, and important here in Philadelphia where resources simply aren’t available.