The Three Problems of the l'S

The L is gone, but you still have the public transportation in New York City. Some parts of Brooklyn had subways built; Chicago tried to replace it with a subway that turned out to be inadequate. In Philly, RL was only converted to a subway for like 15 blocks in the 1950s. One of the other things they might do is relocate the whole thing into a highway median as they did in Chicago and Boston.