> More likely it's just for train maintenance, and indeed, 24-hour train operation is vanishingly rare, with NYC and Chicago the only well-known major cities wi

> More likely it's just for train maintenance, and indeed, 24-hour train operation is vanishingly rare, with NYC and Chicago the only well-known major cities with it. Yes, and at least NYC is notorious for how poorly it's train network is maintained, which I suspect is no coincidence.