Sep 20, 2021 17:00:00

The wheels of railroad cars have been devised so that they are hard to notice even at a glance.

Wheels used in railroad vehicles have protrusions called flanges inside the rails to prevent derailment. However, when turning a curve, it is not possible to turn by simply attaching a flange to the inside of a flat wheel, so it has been devised.

Train Tracks --how trains go round corners | Experiments | Naked Scientists

https://www.thenakedscientists.com/get-naked/experiments/train-tracks-how-trains-go-round-corners

The Naked Scientists, a scientific site, simply shows how the wheels are actually devised using two pipes and tubes that look like rails and a cup that looks like wheels.

Of the cups, the one with the bottom connected looks like this.

On the other hand, the one with the mouthpiece connected looks like this.

All you have to do is roll it on the curved rails. If you roll a PET bottle without any ingenuity, it will roll straight and derail at a curve.

Next, when I rolled the cup that connected the bottoms, it derailed to the right even though it was a left curve.

If it's a cup with a spout connected ...

I rolled along the curve well.

The reason this happens is that 'the curve is longer on the outside than on the inside.'

One solution is to 'run the outer wheels faster, which will drive longer distances'. The automobile is

equipped with a differential device (differential gear) and adopts this method.

The other is to 'enlarge the outer wheels themselves.' The figure below is quite exaggerated, and although it is not possible to run in a straight line as it is, this method was adopted by the railway.

The railroad wheels are shaped like a cup that connects the spouts that came out earlier. For example, when turning to the right, the wheels move to the left side of the rail in the direction of travel, so the left wheel has more ground contact area than the right wheel, and 'the wheels become larger', so the curve turns smoothly. You can do it.

This mechanism is also useful when driving straight. The left and right wheels of a railroad vehicle are connected by an axle, so even if some momentum causes the wheels to shift to either side, the wheels on the side with the larger ground contact area will rotate at higher speed and bend to the other side. It will naturally return to its original state as it creates the power to try.