I road a train once for about an hour. I took a trip up north on Greyhound which I believe is entirely private and I rode the people mover in Detroit once.
The People mover in Detroit is rider funded at a rate of about 7% meaning the other 93% is made up by taxpayer funding in some way or another.
The reason the “fund” is empty is because of theft by the politicians and the unions. Sort of like social security and its vaunted “lock box”. We’ve been hoodwinked by these criminals. Screw’em. Let the fund be empty.