The proposition stated here, that not all restrooms are created equal, may seem trivial and unexceptional. But the principle does crop up in places not always expected. Take the stairways leading down from the upper levels of Amtrak Superliner trains.
First, what’s a Superliner?
Well, outside of much of the East coast, Amtrak runs double decker trains on its long-haul routes. These cannot run in most of the East due to height restrictions mainly for the tunnels getting in and out of New York City. A double decker train means that people enter and exit from the platform on the lower level, then most of them will head upstairs for seating and rooms and meals. Some seats, rooms and luggage storage remain on the lower level. To travel from car to car one must move along the upper level.
Notably, the restrooms are on the lower levels for all but the sleeper cars.
The observant rider will see that the stairwells which provide access to the lower level restrooms are not all the same. Those that are in business class cars or sleeping cars have two railings along the sides, one on each side.
However, in the coach class cars there is only a single railing to assist the struggling passenger on his or her way to relief. And it is an interior rail at that.
This difference in support is significant in my experience.
Pro tip: If ticketed in coach, when in need of relief walk towards the business class car to descend to the lower level restrooms set aside for that car. Though one is not supposed to sit in a business class seat without the appropriate ticket, I am not aware of any regulations specifying which stairs to the lower levels may be used by different Amtrak patrons.