Railbed Backstage, Missoula, Montana

Abandoned homestead buildings always raise to my mind, “Oh, the stories, if walls could speak…”. But until recent Fort Missoula wanders, I hadn’t considered the longevity perspective of a railbed, even with trains being on my "favourite things“ list. 
A reliable source informed me that a railroad spike can stay on the job 35 to 50 years, and sometimes more with exemplary track maintenance. But the routes have stayed basically the same since the first spikes were driven to lay the original rails. Just think of the history that has rolled over the backstage of North American railbeds - troops off to war, adventurers headed west, Mr. Lincoln’s train…. Please add your insight to this list via a Comment below!