🚂 Trains and tracks

A train goes choo-choo and clickety-clack as it rolls along the tracks.

A train is far too heavy and long to steer like a car, so it needs a fixed, smooth path to follow exactly, and metal tracks give it that precise, unchanging route. Steel wheels rolling on steel rails create very little friction, which means a train can pull an enormous amount of weight using surprisingly little energy compared to driving the same weight on a road. Tracks also keep a long train perfectly lined up and stable, since even a small wobble could be dangerous at the high speeds and heavy weights trains often carry.

Train wheels have a small ridge on the inside edge, called a flange, that fits snugly against the inside of the rail and stops the wheel from sliding sideways off the track. Because the two rails are always exactly the same distance apart, the train's wheels are built to match that distance perfectly, so they naturally follow wherever the tracks lead. On curves, the tracks themselves gently bend to guide the train around a turn, rather than the train needing to actively steer itself the way a car does.

Train tracks are two long, shiny metal rails lying side by side on the ground.

People wait at a train station, then get on the train when it stops.

Because steel wheels on steel rails create so little friction, a single powerful engine can pull an enormous number of carriages, far more than any truck could ever tow on a road. Adding more carriages to one train lets it carry many more passengers or much more cargo in a single trip, which is often cheaper and more efficient than running many shorter trips separately. Very long freight trains carrying goods like coal or containers can sometimes stretch for kilometres, connected together by strong couplers between each car.

A train can have many carriages joined together, one after another in a long line.

A conductor checks tickets, helps passengers find their seats, and makes sure everyone gets on and off safely at each station along the route. They also keep an eye on the whole train while it is moving, watching for anything unusual and staying in contact with the driver up at the front. At each stop, the conductor signals when it is safe for the doors to close and the train to continue on its journey.