Essay Sample on What Makes A Steam Locomotive Work?

📌Category: Science, Technology
📌Words: 707
📌Pages: 3
📌Published: 02 September 2021

Steam locomotives, or steam trains. Many people have heard of them, but not many people know how they work. So, how do they work? 

 You need three main elements: fuel (usually coal), water and a footplate crew consisting of a driver and fireman. A steam locomotive is essentially a large energy converting machine. It takes the heat energy from burning fuel and uses this to boil water to create exceptionally high-pressure steam. This pressure energy in the steam is then again converted in the locomotive’s cylinders from pressure to kinetic energy in the form of motion, which is the energy that pulls the trains along.

By far, the most crucial part of a steam locomotive is its boiler. This is where coal is burnt to release vast quantities of heat to boil the water to make the steam. Most of the steam locomotive boilers in the UK operate between 220 – 250 pounds per square inch (psi) of pressure.

The boiler is fitted with at least two safety valves which are set to ‘lift’ and allow steam pressure to escape which stops the boiler from building up excessive pressures. These are fitted on the top of the locomotives boilers and lift often suddenly with large clouds of steam and noise escaping.

A steam locomotive working hard on one trip can boil up to 2,000 gallons of water an hour. The coal is burnt inside the boiler in a furnace called a firebox. With the fire burning on a grate with air gaps that allow oxygen through the burning coal. Which helps it reach the high temperatures needed. A steam locomotive can burn typically 12 tonnes of coal, with a refill done at a mid-point destination.

Coal and water for most steam locomotives are stored in the tender, which is the truck behind where the crew drive the engine from. This is full of water and coal. For example, the ‘Mayflower’ carries nearly 8 tonnes of coal and 4200 gallons of water.[EL4]Water is put into the locomotive boiler under high pressure using a steam-powered device called an ‘injector’. This device uses steam from the boiler to draw water from the tender tank, and inject it into the boiler at an even greater pressure than what the boiler is operating at. It is of paramount importance that the water level in the boiler is maintained at a high level, not only to keep producing steam but because the fire is quickly capable of melting the copper firebox in which it is contained. 

The water level can be checked in the ‘gauge glass’ which shows where the level of the water is in the boiler.

The driver oversees the next part of the locomotive, its cylinders. The driver’s main control is the ‘regulator’ which allows the high-pressure steam to escape from the locomotive’s boiler and enter the cylinders. These are the big red levers, one on each side of the engine. The cylinders are the large metal blocks at platform level at the front of the engine and there is one on each side. Some more powerful locomotives have another 1 or 2 cylinders also inside the engine in addition to those on the outside. 

The cylinders work like a car engine, with high pressure acting on a piston generating large pushing and pulling forces on the piston rod, which can be seen coming out of the back of the cylinders, which connect to the engines ‘driving wheels. 

Unlike a car engine, steam locomotives cylinders have pressure admitted to both sides of the piston, with steam pushing the piston in one direction, and then more fresh steam admitted on the other side to push it back again.

Like feet on a bike pedal, a steam train piston pushes a crank through 180 degrees to cause a rotary motion, before the return of the piston in the cylinder ‘pulls’ the crank back. For each full cycle of the piston, the big driving wheels on a steam locomotive have turned through one complete turn.

The cylinders are set to operate at different points of a wheel turn out of phase to avoid the locomotive getting ‘stuck’ when the crank is at each end; imagine the large driving wheel as a clock face with the first cylinder pushing at 12 o’clock, the second at 3 o’clock, the first cylinder now on its way back at 6 o’clock and finally the second cylinder on its way back at 9 o’clock before the cycle continues over again. This allows a more even distribution of power too.

And that is how a steam engine works!

+
x
Remember! This is just a sample.

You can order a custom paper by our expert writers

Order now
By clicking “Receive Essay”, you agree to our Terms of service and Privacy statement. We will occasionally send you account related emails.