I am pretty well qualified here. I am a terrible geek, an ubergeek. My head is cluttered up with factual material, and hardly any of it is any use at all, though it does make me good at Trivial Pursuit. I’ve never lost a game of that.

I realised just how geeky I am a couple of weeks ago, when I solved a puzzle that had been bothering me since I was about 11 years old. Back in the 50s and 60s, as steam trains got phased out, the favoured train locomotive in the UK was called a Deltic. The reason for this is that the engine had three cylinders in a triangular configuration, resembling the Greek letter delta, hence the name. Each cylinder had not one but two pistons working in tandem opposition. You may, or may not, want to check out what that means. I know, OK? I’m a geek, so I know what it means.

Just to complicate matters, it was a diesel, an engine I understand in theory but am never quite convinced it works. It was also a two stroke, something that I also know, in theory, works but simply don’t believe despite the evidence.

When as a nipper I learned about the deltic layout, I went really geeky. It’s obvious you need three crankshafts to collect the power, and somehow or other they need to be hooked up to the powertrain. But when I made a graph paper model of the setup (I know, it’s tragic isn’t it?) I simply couldn’t figure out how to make it all work. Take my word on this, it will not work if all three crankshafts turn in the same direction. It just won’t. I was stumped. I had on my hands a three cylinder, six piston, two stroke diesel that simply wouldn’t work.

But since I am a true geek, the other day I decided to find out what was going on, some 50 years after I first hit the problem head on. And guess what? I was right all along, but I missed the solution. One of the crankshafts contrarotates. Two of them go clockwise, and the third goes widdershins, or counterclockwise. Then you can link them all up without the thing locking solid.

I did warn you I’m a geek. And yes, widdershins is an old word meaning counterclockwise.