The First Hannibal Bridge was the first permanent rail crossing of the Missouri River and helped establish Kansas City, Missouri as a major city and rail center. The increased train traffic resulting from its construction also contributed to the building of Union Depot, the predecessor to the Kansas City Union Station. After construction was completed, the population of Kansas City began to boom. The bridge was built for the Hannibal & St. Joseph Railroad by the Keystone Bridge Company. Although the railroad became part of the BNSF Railway, the name "Hannibal" has stuck.