Gail,
Here's a bit more info on the lounges:
As a sleeping class passenger you are entitled to utilize Amtrak's first class lounges in DC and Chicago. These lounges are a nice quiet refuge in the often-bustling train station. They have nice plush chairs, conference rooms, computer terminals, newspapers, TV's, luggage storage, free soft drinks, juices, coffee, tea, and clean safe bathrooms. They also allow you to board your train before the rest of the masses.
In DC the Club Acela Lounge is located behind the information kiosk, which is in the center of the waiting areas between gates D & E. There are two large wooden doors there, ring the bell to the right of the door and the attendant will let you in. Show your tickets and you’re in. They will escort you to your train when it’s time.
In Chicago the lounge is called the "Metropolitan Lounge". It is located on the lower level of Union Station, which is also the track level. If you are standing in front of the Amtrak ticket windows, then the Amtrak waiting area is to your left. When you enter the main Amtrak waiting area through a sliding glass door, just walk forward and slightly to the left. There should be another sliding glass door along with a sign, unless they've changed the entrance in the last few months. Again, just show your tickets and ticket stubs from the Capitol and relax.
They'll also give you a card that contains the time that you need to return to the lounge by, in order to board the train and not miss it. If you do leave the lounge, take this card with you as it is also your pass for reentering the lounge. Just wave it at the attendants as you walk in and one will usually look up and acknowledge you and the card. Note the Chicago lounge can be very busy and it sometimes can be hard to get a seat, but you still get the free stuff and priority boarding.