As we wind our way across the rooftops on our journey to London Bridge the man's excitement visibly rises. Nose pressed against the window feverishly trying to jot down numbers in his well-thumbed notebook. Its a busy time, evening rush hour - trains passing, laiden with passengers - his head is swiveling this way and that, desperately trying to make out the last digits of the treasured number. I think this trainspotter is interested in engines, he doesn't note down the numbers of the carriages (but then maybe nobody collects those). There appear to be numbers all over the trains - each carriage has one, each set of doors has them, each engine...
He's wearing a teal fleece and carrying one of those bags popular in the 70s as carry-on luggage. The bag is also green. He's carrying other old well used notebooks - the sort that have an elastic to help keep them shut. He's writing with a very ordinary but totally functional biro.
Watching him there I get this burning desire to ask him what exactly he does. Do you collect engine numbers? What's the aim, to collect all the numbers of all known working engines? What do you do when you have them all? Do you take your numbers home and put them into a database of some sort? How long have you been collecting them? But mostly Why?
As we stand up we are gathering by the door next to each other, and there's this moment when I am looking at him too long and too intently and it makes him catch my eye, that was the moment. And I bottled it, looked away and busied myself with my pass. When we escaped the train I watched him bustle along to the bridge. I expect he was rushing over the platform 6, where the trainspotters tend to gather at the far end. I've seen them, videoing, writing with pencils that have to be licked, or talking into dictaphones. Trainspotting gangs.