People wave at trains. No matter where the train was, if someone was in site they waved. The exception was Reno, Nevada, as the train passed casinos and hotels through downtown. And some rafters on the Colorado River dropped thier pants and showed their best side. Drivers in their cars at train crossings usually scowled. But people outside, railside workers, horse riders, lawn sitters, bike riders, roustabouts, baseball fans at the new Colorado Rockies park, hikers, readers; all waving.
When I was a kid I used to wave at planes when they passed overhead.