At the peak, there were more than 6,000 railway companies in the United States, but now there are more than 500 companies merged, and there are 6 Class I railway companies. Let's talk about the biggest one first, and I basically don't know the rest.
Six major American railway companies:
Union Pacific railway company
BNSF (Burlington North Santa Fe) Burlington North Santa Fe
CSX company
Norfolk South Company
Illinois central gulf company
Missouri-Kansas-Texas Railway Company