When I was growing up, the railroad that I identified most closely with, was the old Baltimore and Ohio (B&O). The Capitol Limited route between Pittsburgh and Washington was as much home to me as the briar patch was home to Bre'r Rabbit. When I started working for Amtrak , one of my earliest assignments was diner service on the Capitol. One winter morning it was still pitch black outside when we started serving breakfast on an eastbound run. I knew we had gone through Pittsburgh and McKeesport on time because I was getting up at the time, but it was too dark to trace our progress. I was pretty sure we were past Connellsville. One of our customers asked me where we were, and I replied that I wasn't sure, but I thought we were nearing Confluence, PA, and I'd tell her more when I had better information. Not five minutes later, she gave a shout and announced to one and all that she had just seen the Confluence Lumber Company!
The B&O tunnels show their age, with heavily weathered concrete portals. I especially like Sand Patch Tunnel at the crest of the Alleghenies; and I like the Magnolia Cutoff east of Cumberland, which features four tunnels and two crossings of the Potomac River. The cutoff was built about 100 years ago to eliminate several much sharper curves, plus the very restrictive Doe Gully Tunnel, which was eliminated back then. Many traces of the old line can still be seen if you know where to look. There have been recent upgrades to that line, so I'm not sure of the current status of those old features.
There are several locations where you can see traces of the old Chesapeake and Ohio Canal.
Harpers Ferry is a unique place that stands out, as well as the Point of Rocks station and the 19th Century shop buildings at Martinsburg, WV.
Old timers sometimes called the B&O the "Best & Only".
Tom
P.S. Nick: Great minds run in the same ruts (or on the same tracks).