I believe Amtrak only owns the platforms and "station area." the old, nice part of the station they do not own. the commuters pay Amtrak for access (or should). union station was designed more as a terminal and for much less commuter traffic than exists today. 30th st was designed as a through station and for more commuter AND intercity service than it handles today. it's an extremely well designed station from a functional point of view. still, DC would have fewer problems if MARC and VRE ran through trains and I'm sure MARC customers would love a l'enfant stop which has much better connections than union station (which, in turn, is great for going to the mall and seeing the museums are meeting with congressman.