By Forrest Whitman Folks who live along what was once the mainline of the Denver Rio Grande and Western Railroad often wax nostalgic. They remember hearing a freight grinding up to Tennessee Pass late at night. For places like Salida, Pleasant Valley and Leadville, the railroad was a source of identity. They felt at home beside the “main line through the mountains.” It’s not all nostalgia. Many of us would love to take the slow train to Denver or Pueblo instead of risking life and limb on U.S. Hwy. 285 or 24. The 1960s were good years for rail passengers. ...