The train doors hissed apart. My youngsters scampered inside the near empty carriage, debating the merits of north-facing window over south. They scooted towards the driver’s door and clambered onto the bench under the largest expanse of window, a foot apart, each claiming the winning view. Babbling to each another, they pressed their noses to the glass as the train glided out of the station.

Teenage son and I sat down beside them. I assessed the couple opposite – a well-preserved grandma in a floppy felt hat and her pint-sized companion, a boy about the same age as my four-year-old daughter. He was sitting quietly, his thonged feet dangling, head bowed, transfixed by the iPad in his lap. Every few moments, he’d jolt into action, little thumbs swiping frantically at the screen, a chorus of bubbles noises accompanying his efforts.