sentences:  It was declared a National Historic Landmark in 1976, for its importance in the state's railroad transportation history, and for the train shed, a rare surviving example of a 19th-century gable-roofed shed (most of which were later replaced by balloon sheds).Amtrak returned to Montgomery in 1989 with an extension of the "Crescent" called the "Gulf Breeze" from Birmingham to Mobile, but Union Station was not used.Instead, Amtrak contracted with a travel agent who occupied a former grain silo nearby.