I gave this a try tonight, and had disappointing results. The problem is that Festool paper uses a wider hole pattern than the Bosch, so you have to make new holes in the paper for the dust collection to work.
The paper itself worked fantastically, with no sign of wear on the grit after about 20 minutes of sanding old ballast and Homasote. Dust collection was poor, but you're not going to get 99% collection with a Festool Sander & Paper combination when removing old ballast. However, it was worse than I remember a Festool sander doing with the same paper.
If anyone has some suggestions for a 24 grit or similar paper that will fit a 5" ROS sander, I'd be happy to give them a try. Otherwise, I'll look in to buying some boulder paper for a 3x21 belt sander.
I'm trying not to compare Festool vs Bosch sanders, that's not the point... but using the one then the other it's easy to see why the higher priced one costs 8 times as much.
Puckdropper