Philadelphia is by no means the perfect urban form, and it has a lot of political handicaps to overcome, some self-inflicted and some imposed from outside. But it has a lot going for it, and a lot of that includes legacy infrastructure from the Pennsylvania and Reading Railroads, and the PRT/PTC and Red Arrow Lines. This city would not be nearly as livable if we didn’t have the physical remnants of Alexander Cassatt’s and Merritt Taylor’s corporate empires scattered everywhere. In fact, that’s the only way, in the long term, to deal with a far-flung and slowly growing city of 1.5 million, in the heart of a 5.8 million person metropolitan region (and a 50+ million megalopolitan region). The 20th Century American dalliance with roads and the automobile is souring, and here we cannot accommodate the scale of volume that we are already attempting. Bicycles are a good last-mile solution, but don’t scale to the distances we often travel in our daily lives (a problem not as prevalent in more compact cities like Portland or Boston).
In short: we have trains, and thank goodness, because we’re going to need them.