History Of A Locomotive 200 BC-Hero of Alexandria created a device called an Aeolipile. A ball containing water was mounted over a cauldron and as it heated, two protruding bent tubes shot out jets of steam causing the ball to spin
1712 - Thomas Newcomen unveiled the first commercially steam engine known as the ‘Newcomen atmospheric engine’. It used steam to power a pump. They were used for pumping water from British coal mines and flooded areas.
1802-Richard Trevithick created the first steam-powered locomotive engine on rails.
1814-George Stephenson built the first practical steam locomotive. It was used to haul coal at Killingworth mine.
Late 18th Century-James Watt improved the efficiency of the stationary engine when patented ‘double acting’ engine that used high pressure steam on both sides of the piston to double the output.
1867-American locomotive designed by Grant Locomotive Works. Known as the American locomotive, this train could follow the tracks and travel on tight bends when on a railway.
Boilers In A Steam Engine Boilers in a steam engine is a device used to create steam by applying heat engery to water. The main boiler used in steam engines are known as a ‘firetube boiler’. This means hot gases pass through tubes running through a sealed container of water and is when transferred through the train to make steam.
A fire-tube boiler used in steam engines were horizontal. The boiler has a cylindrical barrel containing the fire tubes. Then you have the firebox. The firebox is double-walled and is surrounded by water space on five sides. Since most steam engines used coal at the time for fuel, the firebox had a gate covering most of the bottom to hold the fire.
The Piston The piston is located within the cylinder. The purpose of a piston is to help move the crankshaft which is connected to a connecting rod. It transfers force from the expanding gas in the cylinder then to the crankshaft. Within the piston are piston rings. These are iron rings fitted loosely into the grooves. The rings are split at a point in the rim ,allowing them to press against the cylinder with a slight spring pressure. Pistons are cast from aluminium alloys. In some steam engines, the piston can also act as a valve by covering and uncovering ports in the cylinder.
Piston Rings A piston ring is a split ring that fits into a groove on the outer d iameter of a piston in a steam engine. The main functions of piston rings include ; Sealing the combustion chamber so that there is minimal loss of gases to the crank case. Improving heat transfer from the piston to the cylinder wall. Maintaining the proper quantity of the oil between the piston and the cylinder and regulating engine oil consumption by scraping oil from the cylinder walls back to the sump.
Cylinders In A Steam Engine A cylinder is the power-producing element of a steam engine powering a steam locomotive. The cylinder is made pressure tight with end covers and a piston. As steam locomotives were just being invented, the material used to make these cylinders were cast iron but later changed to steel. In early locomotives, the cylinders were usually positioned vertically and the motion was transmitted through beams. On top of the cylinder lies the valve chest. But in older locomotives, they were sometimes located alongside the cylinders and inserted through slots in the frames. While the cylinders were outside, the valves were inside and could be driven by inside the valve gear. In early locomotives, if the cylinders were small, the valve chests would of been located between the main cylinders. But sometimes, they could be found underneath the main cylinders.
The Tender Carriage The tender carriage is a special coal-car used to haul coal by a steam locomotive. It contained coal and water. Since locomotives consumed large ammounts of water and coal, it was necessary to keep them running over long distances. In early days of locomotives, the tender carts were rectangular boxes with a bunker of coal surrounded by a U-shaped water jacket. This design was used up until the end of steam locomotives that required coal to move. Locomotives that don’t have tenders and carry all their fuel and water on board were called Tank Locomotives. Also known as Garrats.
The Wheels Of The Locomotive
On a steam locomotive, a driving wheel is a powered wheel which was driven by the locomotives piston. The driving wheels are all coupled together with side roads. These side rods were normally one pair which was directly driven by the main rod which is connected to the end of the piston. The driving wheels are usually larger than the leading or trailing wheels. Since locomotives were directly driven, one of the few ways to gear it for a good performance was to make sure the wheels were the right size.
How The Steam Works
The production of steam begins with the fire-box. Hot gases rise from the firebed to the upper portion of the fire-box. The gases move from the fire-box through pipes known as ‘flues’ which are filled with water. Heat from the gases in the flues brings the water to a boil making steam. When the steam is made, it makes it’s way to the top of the boiler and is collected in the dome. As the steam gets collected in the dome, the built up pressure gives way creating the ‘choo choo’ sound.