Did+steam+really+die?

Steam engines were gradually replaced by diesels. It's ironic that some of the older diesels are now being preserved on heritage lines and treated with almost as much reverence as steam engines. This one is a preserved British Rail Class 55("Deltic"), number 55022, called Royal Scots Grey dating from 1960. So it's actually older than some of the very last steam trains that were made. Coal was a cheap and abundant fuel during the early Industrial Revolution, but the invention of the gasoline engine (petrol engine) in the mid-19th century heralded a new era: during the 20th century, oil overtook coal as the world's favourite fuel. Steam engines are extremely inefficient, wasting around 80-90 percent of all the energy they produce from coal. That means they have to burn enormous amounts of coal to produce useful amounts of power. A steam engine is so inefficient because the fire that burns the coal is totally separate (and often some distance from) the cylinder that turns the heat energy in the steam into mechanical energy that powers the machine. This design is called an external combustion energy because the fire and boiler are outside the cylinder. It's inefficient because energy is wasted as the heat and steam travel from the fire, via the boiler, to the cylinder. Gasoline- and diesel-powered engines are based on a totally different design called an internal combustion engine. The gasoline or diesel fuel is burned inside the cylinder, not outside it, and this makes internal combustion engines considerably more efficient. Oil has many other advantages too: it's cleaner than coal, makes less air pollution, and is much easier to transport in pipes.

That's largely why steam locomotives disappeared from our railroads. Diesel locomotives were altogether more convenient. It takes hours to fire up a steam engine before you can use it; you can get a diesel engine running in less than a minute. Steam engines disappeared from factories when electricity became a more convenient way of powering buildings. Who wants to load coal into a factory every day when they can just flick on switches to make things work? But things are not quite what they seem. Steam and coal never did disappear.. not exactly. Where does the electricity we use come from? Well, a great deal of it still comes from coal, burned in power plants miles away from our homes and factories. Inside a coal-fired power plant, coal is still burned to make steam, which drives windmill-like devices called steam turbines, which are much more efficient than steam engines. As they rotate, they turn electromagnetic generators and produce electricity. So, you see, although steam locomotives have vanished from our railways, steam power iis alive and well.. and just as important as it ever was.

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