Well, enlighten us. How big are the shelves? How many of them are there? 5x50 lb bags per shelf doesn't mean the baggage car can only carry 5 bags. How preposterous. I'm sure the majority of the 50+ lb'ers will be on the ground. Not every checked bag is 50 lbs.
You know, even if the 250lbs/shelf is true, I don't see that being a huge problem.
I found this picture:
http://history.amtrak.com/archives/viewliner-ii-baggage-car-interior-2013that I had not found before.
If I'm counting correctly that's 10 shelves per side, for a total of 20 shelves. I'm assuming there's none behind the photographer and beyond the far set of doors there are none.
So right there that's 5000lbs of shelf space.
But it looks like the one reason for the bottom set of shelves is simply to keep bags sorted (and off the dirty floor). So in theory you could just fold those up and use the floor.
Also looking further, that looks like nylon webbing, which given the size of the strap is probably easily rated for over 2000lbs, easily.
So, maybe the shelves are an issue, or maybe not, but I doubt it's a show stopper.