IT used to be that fathers bonded with sons over shared interests, like baseball and fast cars — the child striving toward adulthood, the father yearning for boyhood. In my case, I hung out with my dad in used-book stores. But for most hyperextended fathers in today’s media-swamped world, it’s not that simple.

I mean, how does a dad with Lincoln-Log hands bond with his kid over an Xbox, fumbling to manipulate a dual controller and focus on digital pandemonium?

Eric, the oldest of my three sons, who is now 37, tagged along on many of my reporting trips for a newspaper column I once wrote called “Maryland Life.” My middle son, David, at 17, prefers to bond over meals in restaurants. But Aaron, who is 14, is an unabashed trainiac, channeling my late father-in-law, a physician who spent his life smitten with trains and trolleys.

Fortunately, Aaron has defined our times together in a way that suits us both. He doesn’t just like rails and trains — they are his passion. He loves riding them. He loves watching them. So, off we go, on excursion after excursion...