Freight railroads are highly regulated in the same sense that police departments are highly regulated. There are lots of rules that apply, but they generally decided to make (or accept) those rules themselves. And the entrenched players make it almost entirely impossible for outside forces to enact change on the system as a whole.

Your comment is accurate, I just want to put this here as an analogy to help people in case they read your comment as a defense of PSR or the rail industry as a whole.