I'll definitely agree that the toilet is an oddity, especially if you're traveling with a parent, friend, etc. Really any situation other than solo. :lol: I don't think you're likely to see a Viewliner shell running as the new fleet for the NEC though. Unless they make changes to the structural integrity and configuration it won't happen. They're not going to lose 15 MPH on every train because of a common shell. In all likelihood none of us know what the new cars will likely look like, because a new design will probably be dreamed up. In all reality the design of the Amfleets isn't too bad except for the size of the windows. If you can put in larger windows, why not just go with the same design?
There is nothing limiting the Viewliners speed except for the trucks. There is simply no reason to maintain Viewliner equipment to speeds higher than 110, because that's what the Heritage cars they run with are limited to. From what I understand, the new series of "conventional" equipment will be Viewliner shelled, LD with one Vestibule as: Baggage, Baggage-Dorm, Diner, Sleeper, coach, and lounge, and two-vestibule SD in coach, food service, and business class. With 125 speed rated trucks.
As for the "structural integrity of the trapezoidal shape", I assume you are talking about the structural integrity of the Viewliner, rather than the OTHER trapezoidal Amtrak car, the Acela?
Lastly, the Surfliners and California cars are rated for 125 already, with two door openings. A 125-mph, 1-door Superliner would not be impossible, or even difficult. In fact, I can't think of a reason why the existing Superliners could not be upgraded.
I've always found that the Lounge toilets to be in the most decent shape of the public toilets. Most people don't know that they exist, and are never close enough to it that it's the closest one to them.
I, personally, have NEVER seen a Diner-Lite configuration car with an unlocked bathroom. Some are locked, others just don't have them.