You could ask Francis Bourgeois, a young, geeky and famous train guy. youtu.be/JVJT6Gw4ehM?...

UK social media star spreads joys to millions through ‘trainspotting’

YouTube video by TODAY

That's like a variation on the spreadsheet fetish, isn't it? I've heard of trainspotters, but don't have a clear understanding of what they do.