Strangely enough, I'm going to ask a serious question here . . .
Back in the olden days, when johns flushed directly onto the tracks, was Amtrak as concerned (or even more concerned) about the biodegradability of its TP?
Wasn't Amtrak's tracks (except for the NEC), so why should they care? Let UP's tracks get rotted to, er, crap...
Well - there wasn't any Amtrak in those days. Each railroad had passenger and freight on its own tracks.
I remember those days and being able to see the ground speed by when you flushed the commode in the restroom of the car.
I also remember the conductors came through all the cars and locked the restrooms as we approached the stations so no one would flush while in the station.
Many years ago.