I heard them before I saw them: 'If you're happy and you know it, clap your hands.'
About ten knee-high children were hoarded together under the platform shelter with a group of grinning adults around them - a collection of middle-aged parents each similarly dressed: blue cagouls, grey back-packs, jeans trailing over track shoes, their eyes catching mine.
'If you're happy and you know it, shout 'I am.''
I too must have once had this ability to be so ecstatically happy to order.
One man, a father, smiled determinedly in my direction. There was something evangelical about that grin, something too earnest, something that made me glance downwards at the railway track.
An overhead cloud released a fresh torrent.
I walked further down the platform until I was out of earshot.