3 ms·

I know NYC has extremely construction costs per mile but I've never heard that about Chicago, Washington DC or Philadelphia.

• barbecue_sauce 6y ago
  Philadelphia hasn't really expanded its subway system since the 1950s as far as I can tell. Only a few renovations of certain stretches of track (much of which is actually elevated, not underground). Even then, its not a very extensive system; just a north<->south line and a northeast<->west line.