Don't know if it's true or not but I heard a story where the Superliner cars used to dump their waste after they exceeded 20 MPH or so. This prevented them from dumping while they were taking on passengers while stopped at stations. Supposedly the Empire Builder was crossing the Salmon Bay drawbridge near the Ballard Locks in Seattle and one of the cars dumped its sewage through the drawbridge as a pleasure craft owned by a very powerful and influential individual was passing underneath. This person had enough political influence that a few phone calls or irate letters led to some drastic changes in how railroad cars handled the sewage issue. Maybe it was Bill Gates or the CEO of Boeing.