Though they're not a primary mode for travelers, trains are essential. In the 200 or so years they've existed, they've been used to handle a variety of tasks and have become vital all over the globe. They're quick, safe, and dependable as evidenced by some of the oldest locomotives still in service today .
Naturally, trains have transformed since the first models hit tracks back in the 1800s. Countless engineers have come along to improve upon them, resulting in major innovations like the fastest passenger trains around the world . Still, despite their prevalence, the science behind trains isn't something most people understand.
It can be hard to fathom how they manage to stay on track. They're massive, heavy, and move at remarkable speed, so what keeps them from going off the rails? The answer lies predominantly in the shape of their wheels. They're slightly conical in shape, with the inside of the wheel having a larger circumference than the outside.
The inside also has a raised edge on the inner side to keep the train attached to the track. When a train turns, centrifugal force pushes the outside wheel to the larger portion of the cone while pushing the inside wheel to the smaller part. This keeps the train from derailing when turning.
While this wheel engineering is impressive, it's not foolproof. Due to a variety of factors, sending a train off-track can and occasionally does happen. The train wheels we know today have been around for decades upon decades.
In that time, .