I think that's smart. Though the Capitol Limited from Chicago is scheduled to leave Pittsburgh at 5:20 a.m., a few hours' delay is unfortunately common, and it's not at all unusual for it to leave after the Pennsylvanian chugs out at 7:30. (Almost invariably on time, 'cause Pittsburgh is the origination.) So why not stay on the CL, get some uninterrupted sleep, and enjoy the beautiful scenery in the Laurel Highlands when you wake up. And don't worry (within reason) when you'll arrive in Washington. Trains to Philly leave all day.