Carknocker,
Ok, here are the directions to the various lounges. Since you didn’t indicate where you were starting from, I’m also going to enclose the directions to Chicago’s Metropolitan lounge just in case.
Your sleeper tickets qualify you as a First Class passenger on Amtrak. As a first class passenger you are entitled to utilize Amtrak's first class lounges in NY, 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, 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 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 and facing 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 noting the lounge.
Just show your tickets to one of the attendants at the counter inside. They will give you a pass that will allow you to come and go, as you like until your trains departure. So you can either just relax in the lounge or you can wander about the station. There are several places within the station to buy lunch, if you like. 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. For this reason they will make you leave your carry-on bags in the luggage room inside the lounge, you cannot take them to your seat due to the crowded nature of the lounge.
I will also mention that there is a locked luggage area for first class passengers. You can find this room by making the first right after you walk through the first set of sliding glass doors that I mentioned above. Walk down a short hall towards the south waiting area and again make the first right available. This is where I usually leave my bags when I go through Chicago, as opposed to the unlocked side room in the actual lounge. I’ve never heard of any bags being stolen from the unlocked room, but there have been a few cases of people grabbing the wrong bag by accident. Also don't leave any important medicines in your luggage while in Chicago, keep it with you.
If you choose that latter alternative to store any carryon luggage, when they make the first call for those people who need redcaps, you should go get your bags out of the locked room. Then you can return to the lounge and board with the rest of the passengers, or you can allow the redcap to escort you and carry your bag to the train, although that will make your wallet a little lighter.
In NY and DC the lounges are called “Club Acela”. The lounge in NY can be found to the far left of the NJ Transit ticket windows as you face them. Walk past the West Gate for tracks 7 & 8 on the left side of the escalator and you will see a sign on the corner of the wall. There is a doorbell to the left of two gold doors. Ring the bell and wait for the click to open the door. Note: In NY there is no pre-boarding ahead of the regular passengers, but they usually do announce your train in the lounge before they announce it in the main station. This means if you don’t dilly-dally, you can generally be near the head of the line at the escalator.
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.
As for First Class vs. Business Class, here are the big differences. FC has 2 & 1 seating as opposed to the normal 2 & 2 seating. This allows for wider, more roomier chairs than you would find in either coach or business class on any Amtrak train. Next is the food, in BC its typical café food and you get to pay for it. In FC you get hot meals served to you at your seat. While it may not be the same quality as you might find at the Ritz, it’s definitely better than any airline food I’ve ever had.
There are typically 3 main choices, along with a lighter fare for those who may not be overly hungry. All meals come with free beverages, and during lunch and dinner times that includes alcohol. They offer wine, beer, and a selection of hard liquor. There is no charge for the liquor and it’s basically all you can drink, unless of course they run out of what you’re drinking.
Finally, although minor, you also get a free newspaper and free headphones to use with the onboard audio/news system. You can even take the headphones home as a souvenir, if you like as they do say Acela on the sides.
Don't hesitate to ask if you have any more questions, or if something is not clear.