While we are on the subject of railways today, I must mention a happy meeting I had a couple of weeks ago with a fellow train-spotter.

This was Frank Close, the Professor of Physics at Oxford University, whom I met at St Edmund Hall at a lunch that preceded his delivery of the Gibraltar Lecture given as part of the FT Weekend Oxford Literary Festival.

This dealt with the fascinating subject of Harwell physicist Bruno Pontecorvo, who disappeared from his post in 1950, only to turn up in mysterious circumstances on the other side of the Iron Curtain, as described in Prof Close’s book Half Life.

Moving from the Iron Curtain to iron roads, how was it, you might wonder, that our shared enthusiasm for collecting engine numbers came to be known?

The answer is simple: Prof Close, who lives in Abingdon and is a reader of The Oxford Times had learned of my enthusiasm from Gray Matter.

More than trains connects us, however. For the professor had also picked up that both of us were from Peterborough and educated at its rival grammar schools, me at Deacon’s School, alma mater, too, to my one-time journalistic colleague Richard Littlejohn, he at King’s School, where my great-niece now studies.

For those of us brought up in the Peterborough of the 1950s, it was hard not to be captured by the magic of railways, with gleaming giants like the record-breaking Mallard and other of Sir Nigel Gresley’s A4 Pacifics a daily sight on the tracks.

That there was a powerful Midland Region presence in the city as well made it a rich hunting ground for spotters.

“Did you bunk sheds too?” asked Prof Close’s wife as we moved into the dining hall. I admitted that, yes I did. Didn’t we all?