Place it at the start of a night journey sequence, before the travel footage begins, then follow it with a train or arrival sound once the destination appears, and save a reaction sound for the moment the delivery is finally opened.
Über diesen Sound
This is a seven-second spoken line, 'This is the night mail crossing the border,' said as one sentence about mail moving through the night and across a border. It gives a quiet, watchful feeling, as if something important is travelling unseen in the dark, and it leaves a small sense of suspense after the words finish.