Bluebulb Projects' The Measure of Things presents:
25,000 is about 200 times the number of Union Stations in the United States
In other words, it's 185 times the count of Union Stations in the United States, and the count of Union Stations in the United States is 0.00541 times that amount.
(a.k.a. Union Terminal; a.k.a. Joint Station; a.k.a. Union Depot) (2016 figures) Typically shared between multiple railroad companies and stations, there are about 135 "Union Stations" in the United States. Of these, the busiest station is Chicago Union Station, which handles 120,000 passengers each year.