Refrigerator car

I don’t get to spend as much time in train stations as I like—ah, the romance of travel—but last week I had occasion to pass through South Station, the main commuter-rail/Amtrak hub in Boston. And there’s an odd bit of sound design that’s been built into the place.

If you’re reasonably old, you remember the kinds of schedule boards they used to have in train stations, the ones where locations and numbers are printed on tiles that spin around whenever the sign is updated. They’re like giant versions of pre-LED digital alarm clocks. (The technical name for them is a “split-flap” display.) South Station still has a couple of those boards, but they’re not in use, having been replaced by a giant digital LED board.

But this is what’s weird—there’s a speaker mounted near the board, and every time it (silently) updates, the speaker pipes in the clacking sound of the rotating tiles on an old-fashioned board. (It turns out the Globe reported on this feature back in 2006—as far as I know, it's still unique.) If you grew up with the old boards, you hear the sound, you look up to see what’s changed. But we’re now into generations that will be mystified as to why board updates are announced with this strange rattle of percussion. (There weren't that many of the old generations, actually—split-flap signs didn't become common until the 1950s.)

There is, I imagine, an entire category of sounds like this, technically obsolete but still hanging on (for another example, I can set my mobile phone ringtone to a recording of an old-time telephone bell). I wonder if these sounds will become the aural equivalent of particularly obscure sayings or turns of phrase, where the colloquial meaning still remains widely intelligible even as the literal meaning becomes increasingly baffling.