A stationary steam engine uses steam power to drive instruments other than themselves. They were usually used to power bridges, barriers, drive mills and factory machinery. Later models were used to generate electricity. Such engines work from a fixed position and are not used as modes of transport, though some have been used to drive wheels on steam ships.
Basic steam engines work when high-pressure steam is allowed into a cylinder. This cylinder has a piston that is pushed in one direction by the steam, expelling cooled exhaust steam out of a vent and creating movement through the piston rod. This movement moves the wheels of a steam train, pushing the engine forwards. Such engines push the piston one way, then the other way by alternating which end of the cylinder the steam enters.
The first stationary steam engine was invented by Thomas Savery and then improved upon by fellow Englishman Thomas Newcomen and Scot, James Watt. In 1698, Savery invented a steam engine that would pump water out of a Cornish coal mine. His basic design was improved upon in the 18th and 19th centuries, but was replaced by electricity and the combustion engine in the 20th.
In 1705, Newcomen invented the first beam engine. This stationary steam engine employed a pivoted beam linked to a vertical piston-cylinder below. Watt, amongst others, improved the engine by adding a compressor. The beam engine was used primarily to pump water and to run mill wheels. It was also employed on steam ships.
A short-lived variant of the immovable engine was the table engine. This engine was similar to the beam engine, but sat upon a table-base and was connected to a fly-wheel via a connecting rod and cross-head. James Sadler invented the engine and used it at the Portsmouth Block Mills. Compared to other engines, it was both slow and weak.
George Henry Corliss, an American, added rotary valves to the basic stationary steam engine idea to create the Corliss engine. First built in 1848, the Corliss allowed for variable timing in the operation of its valves. It was mostly used for shafting in factories and the generation of electricity using dynamos, as it was very fuel-efficient.
In 1828, James Perkins developed the Uniflow engine that used a half-cylinder and allowed the piston to move in only one direction. As the exhaust and fuel steam always entered their same respective ends of the cylinder, it lead to increased heat efficiency. The Uniflow was adapted for various steam engines, but was mostly used for generating electricity.
British inventor James Hornblower created the first compound stationary steam engine in 1781. He reasoned that if energy and action can be generated from pressurized steam in one cylinder, then the same steam could be moved into another cylinder to generate more power. Hornblower built engines where there were at least two cylinders and each piston after the first reacted to lower pressure.