Only the Sunset Limited has had the lounge car eliminated so far, and it had nothing to do with the plan that Amtrak calls Diner Lite. That plan, Diner Lite, combines the lounge car and the dining car into one car. The Sunset Limited is still running with a full dining car. The lounge, as noted by Ssullivan, was in the bottom of a coach car. Amtrak has a few of these coach cars that were built for short haul runs, with cafe facilities on the lower level.

I heard nothing on a time table for the implementation of Diner Lite so far, thankfully. It may still be coming, or it may be that Amtrak is waiting to see what SDS (Simplified Dining System), which reduced staffing in the dining cars, saves in terms of money.

I do know that 2 cars have come out of Beach Grove (Amtrak's heavy maintenance/rebuild facility), rebuilt for Diner Lite. But two is not enough to impliment the plan, and those 2 came out several months ago. I haven't heard that any more are actually under construction.