For years I was convinced that I knew how trains worked; an engine makes them go and flanged wheels keep them on the tracks. Although I had never really given it much thought, in my head I knew how they worked.
There was zero doubt in my mind that I had it wrong or that I was leaving something out. If you can’t tell where I’m going with this, I was wrong; the truth of how they work is so much cooler then I’d ever thought.
I’m well aware that a picture paints a thousand words, so I’ve included a video below, but the reality is that train wheels use a clever geometry trick to stay on the tracks and go around turns.
Train wheels are both tapered and flanged – the taper has them shaped with a larger radius on the inside then the outside. Along with this, the left and right pair of wheels are directly connected, meaning they are always rotating at the same speed.
But what happens when the train comes to a bend? If both wheels are rotating at the same speed, how does it turn? Well, what happens is that the inside wheel ends up riding on a smaller section of its taper, and the outside wheel on a larger section. And now, because the outside wheel travels more distance then the inside, the train ends up turning.
My mind was blown. Totally blown. When I realised how trains actually worked, I realised my thinking was totally flawed. I had taken the mechanics of trains to be so simple that it needed no thought. I had assumed that I had it fully understood and that was it.
It’s something I think about a lot though, and something you should too – how many things are there out there that we “understand”, but in reality couldn’t be further from the mark? How much better would we be if we approached all of life with that frame of mind?
Food for thought.
Anyway, here’s a great video that covers it much better then I just did.