The big facts page

115 steam engine facts, all checked

Every fact on this site in one place, each linked to Encyclopaedia Britannica, NASA Glenn Research Center or the Science Museum Group blog. Our build checks each one against the source text; see the sources page.

How steam engines work

1 A steam engine is a machine that uses steam to do mechanical work, with heat doing the pushing. Encyclopaedia Britannica: steam engine
2 In the classic engine the piston rod drives a crank on a flywheel, which turns the back-and-forth push into round-and-round motion. Encyclopaedia Britannica: steam engine
3 In a double-acting engine, steam from the boiler is let in to each side of the piston in turn, so it pushes both ways. Encyclopaedia Britannica: steam engine
4 In a steam turbine, the steam rushes out of nozzles at high speed and spins the blades directly, with no piston at all. Encyclopaedia Britannica: steam engine
5 A steam turbine is a rotor sitting on bearings inside a cylindrical casing. Encyclopaedia Britannica: steam turbine
6 A flywheel’s inertia resists changes in speed, smoothing out the jerky pushes of the piston. Encyclopaedia Britannica: flywheel
7 Spin a flywheel twice as fast and it stores four times the energy. Encyclopaedia Britannica: flywheel
8 Boilers come in two big families: fire-tube boilers, where hot gas runs through tubes inside the water, and water-tube boilers, where the water runs through tubes inside the fire. Encyclopaedia Britannica: boiler
9 In the mid-1600s Robert Boyle studied how the pressure and volume of a trapped gas are linked. NASA Glenn Research Center: Boyle’s law
10 Gas pressure comes from molecules in constant, random motion, banging into each other and into the walls. NASA Glenn Research Center: gas pressure
11 Boyle found that pressure times volume stays nearly constant: halve the space and the pressure goes up to match. NASA Glenn Research Center: Boyle’s law
12 NASA’s worked example: a gas filling 4.0 cubic metres at 1.0 kilopascal shrinks to 3.0 cubic metres when the pressure rises to 1.33 kilopascals. NASA Glenn Research Center: Boyle’s law
13 Power is how fast work gets done: the rate of change of work over time. NASA Glenn Research Center: work
14 Physicists define work as force times the distance something moves. NASA Glenn Research Center: work
15 Work is measured in joules: one joule is one newton pushing through one metre. NASA Glenn Research Center: work
16 One horsepower is 33,000 foot-pounds of work a minute. Encyclopaedia Britannica: horsepower
17 James Watt fixed the horsepower after experiments with strong dray horses, and his figure is about 50 per cent more than an average horse can keep up. Encyclopaedia Britannica: horsepower
18 One horsepower is about 746 watts. Encyclopaedia Britannica: horsepower
19 Water-tube boilers took over when power stations needed huge amounts of steam at pressures fire-tube boilers could not reach. Encyclopaedia Britannica: boiler

Hero and Papin

20 Hero of Alexandria made the first known “steam engine”, but used it only to power toys and amuse visitors. Encyclopaedia Britannica: Heron of Alexandria
21 His book Pneumatica describes singing birds, puppets and coin-operated machines, as well as the aeolipile. Encyclopaedia Britannica: Heron of Alexandria
22 The aeolipile is a ball on a boiler with two angled nozzles: steam squirts out and the ball spins. Encyclopaedia Britannica: Heron of Alexandria
23 Hero flourished around AD 62. Encyclopaedia Britannica: Heron of Alexandria
24 In 1679 Denis Papin invented his steam digester, an early pressure cooker. Encyclopaedia Britannica: Denis Papin
25 Papin had the idea of steam driving a piston in a cylinder, but never built an engine of his own. Encyclopaedia Britannica: Denis Papin

Savery and Newcomen

26 Thomas Savery was born around 1650 at Shilstone in Devon and was a military engineer by trade. Encyclopaedia Britannica: Thomas Savery
27 In 1698 Savery patented a steam pump: a closed vessel filled with water, with steam let in and then condensed. Encyclopaedia Britannica: Thomas Savery
28 A sprinkler of cold water condensed the steam, making a vacuum that sucked water up. Encyclopaedia Britannica: Thomas Savery
29 Savery’s improved pump used two vessels, so one could fill while the other emptied. Encyclopaedia Britannica: Thomas Savery
30 Savery pumps found work supplying water to large buildings. Encyclopaedia Britannica: Thomas Savery
31 Their weak point was high-pressure steam, above about 8 to 10 atmospheres. Encyclopaedia Britannica: Thomas Savery
32 Savery also invented an odometer for measuring how far ships had sailed. Encyclopaedia Britannica: Thomas Savery
33 Savery’s pump was nicknamed the “Miner’s Friend”. Science Museum blog: In pursuit of power
34 Thomas Newcomen was baptised on 28 February 1664 in Dartmouth. Encyclopaedia Britannica: Thomas Newcomen
35 Newcomen was an ironmonger who saw how much it cost to use horses to pump water out of Cornish tin mines. Encyclopaedia Britannica: Thomas Newcomen
36 With John Calley, a plumber, he experimented for more than ten years. Encyclopaedia Britannica: Thomas Newcomen
37 In a Newcomen engine the air does the pushing: steam is condensed to make a vacuum in the cylinder, and atmospheric pressure shoves the piston down. Encyclopaedia Britannica: Thomas Newcomen
38 Because Savery held a broad patent from 1698, Newcomen could not patent his own engine. Encyclopaedia Britannica: Thomas Newcomen
39 The first recorded Newcomen engine was put up near Dudley Castle, Staffordshire, in 1712. Encyclopaedia Britannica: Thomas Newcomen
40 The Science Museum calls 1712 “a red letter year” for steam. Science Museum blog: In pursuit of power
41 Newcomen’s engine had an internal jet condenser and valve gear that worked itself. Encyclopaedia Britannica: Thomas Newcomen
42 Newcomen engines drained mines and raised water to drive waterwheels. Encyclopaedia Britannica: Thomas Newcomen
43 The Science Museum’s Pentrich engine, an atmospheric engine, was built by Francis Thompson in 1791. Science Museum blog: In pursuit of power

James Watt and Matthew Boulton

44 The watt, the unit of power, is named in honour of James Watt. Encyclopaedia Britannica: watt
45 James Watt was born on 19 January 1736 in Greenock, Scotland, and died on 25 August 1819 at Heathfield Hall. Encyclopaedia Britannica: James Watt
46 At 17 Watt decided to become a mathematical-instrument maker, and in 1755 went to London to learn the trade. Encyclopaedia Britannica: James Watt
47 In 1757 he opened a shop at the University of Glasgow. Encyclopaedia Britannica: James Watt
48 In May 1765 Watt came up with the separate condenser, his first and greatest invention. Encyclopaedia Britannica: James Watt
49 His patent was granted on 5 January 1769, titled “A new method of lessening the consumption of steam and fuel in fire-engines”. Science Museum blog: James Watt and the separate condenser
50 The Science Museum blog calls the separate condenser the “greatest single improvement ever made to the steam engine”. Science Museum blog: James Watt and the separate condenser
51 Watt’s engines burned two-thirds less coal than Newcomen’s. Science Museum blog: James Watt and the separate condenser
52 When Watt’s backer John Roebuck went bankrupt in 1772, Matthew Boulton took a share in the patent. Encyclopaedia Britannica: James Watt
53 In 1775 Watt and Boulton began a partnership that lasted 25 years. Encyclopaedia Britannica: James Watt
54 Watt’s sun-and-planet gear (1781) turned a shaft twice for every cycle of the engine. Encyclopaedia Britannica: James Watt
55 In 1782 Watt patented the double-acting engine, where the piston pushed as well as pulled. Encyclopaedia Britannica: James Watt
56 Watt called his 1784 parallel motion “one of the most ingenious, simple pieces of mechanism I have contrived”. Encyclopaedia Britannica: James Watt
57 At Boulton’s suggestion, Watt added a centrifugal governor to control the engine’s speed automatically. Encyclopaedia Britannica: James Watt
58 By 1790 Watt had added a pressure gauge. Encyclopaedia Britannica: James Watt
59 Watt’s rotary engines drove machines in factories such as cotton mills. Encyclopaedia Britannica: James Watt
60 Watt earned £76,000 in royalties. Encyclopaedia Britannica: James Watt
61 In 1785 Watt and Boulton were elected fellows of the Royal Society. Encyclopaedia Britannica: James Watt
62 In 1762 Matthew Boulton built the Soho Manufactory near Birmingham. Encyclopaedia Britannica: Matthew Boulton
63 Boulton met James Watt in 1768. Encyclopaedia Britannica: Matthew Boulton
64 In 1786 Boulton put steam power to work making coins. Encyclopaedia Britannica: Matthew Boulton
65 By 1800 almost 500 Boulton & Watt steam engines had been installed. Encyclopaedia Britannica: Matthew Boulton
66 Watt added a flywheel to his engine design in 1788. Encyclopaedia Britannica: James Watt

Richard Trevithick

67 Richard Trevithick was born on 13 April 1771 in Illogan, Cornwall. Encyclopaedia Britannica: Richard Trevithick
68 A schoolmaster called young Trevithick “disobedient, slow and obstinate”. Encyclopaedia Britannica: Richard Trevithick
69 Watt thought “strong steam” (high pressure) was too dangerous to harness; Trevithick went for it anyway. Encyclopaedia Britannica: Richard Trevithick
70 Trevithick built 30 small high-pressure engines that could be carried on an ordinary farm wagon. They were known as “puffer whims”. Encyclopaedia Britannica: Richard Trevithick
71 On 21 February 1804 a Trevithick engine won a bet by hauling 10 tons of iron and 70 men along 10 miles of tramway. Encyclopaedia Britannica: Richard Trevithick
72 In 1808 his locomotive Catch-me-who-can ran on a circular track near Euston Road in London. Encyclopaedia Britannica: Richard Trevithick
73 The trouble was the track: cast-iron rails were too brittle for heavy engines. Encyclopaedia Britannica: Richard Trevithick
74 Nine of Trevithick’s engines were ordered for silver mines in Peru, and he sailed to South America in 1816. Encyclopaedia Britannica: Richard Trevithick
75 Richard Trevithick built a small model locomotive in 1797 to test his ideas. Science Museum blog: Steam train in Kensington Gardens
76 Trevithick built the world’s first steam railway locomotive in 1804. Science Museum blog: Steam train in Kensington Gardens
77 His father, a mine manager, thought he was a loafer, and Trevithick stayed barely able to read and write all his life. Encyclopaedia Britannica: Richard Trevithick
78 Nicholas-Joseph Cugnot built a clumsy steam carriage for roads in France as early as 1769. Encyclopaedia Britannica: steam engine
79 Trevithick’s 1804 run was on a horse tramway in Wales. Encyclopaedia Britannica: steam engine

Puffing Billy, the Stephensons and Rocket

80 Puffing Billy, built in about 1814 by William Hedley, is the oldest surviving steam locomotive in the world. Science Museum blog: Steam train in Kensington Gardens
81 In 1812 Hedley built a test rig to check whether smooth wheels could grip smooth rails. Science Museum blog: Steam train in Kensington Gardens
82 George Stephenson was born on 9 June 1781 at Wylam, near Newcastle. Encyclopaedia Britannica: George Stephenson
83 By the age of 19 he was running a Newcomen engine. Encyclopaedia Britannica: George Stephenson
84 He went to night school to learn to read and write. Encyclopaedia Britannica: George Stephenson
85 To earn extra money he learned to mend shoes and fix clocks. Encyclopaedia Britannica: George Stephenson
86 He became engine wright (chief mechanic) at Killingworth colliery. Encyclopaedia Britannica: George Stephenson
87 His engine Blucher pulled eight wagons carrying 30 tons of coal at 4 mph (6 km/h). Encyclopaedia Britannica: George Stephenson
88 Stephenson used the “steam blast”: exhaust steam sent up the chimney pulling air after it and boosting the draught. Encyclopaedia Britannica: George Stephenson
89 Robert Stephenson, George’s son, was born on 16 October 1803 at Willington Quay. Encyclopaedia Britannica: Robert Stephenson
90 In 1833 Robert became chief engineer of the London and Birmingham Railway. Encyclopaedia Britannica: Robert Stephenson
91 Robert Stephenson also designed the Britannia Bridge over the Menai Strait. Encyclopaedia Britannica: Robert Stephenson
92 Rocket was built in 1829 by Robert Stephenson and Company at the Forth Street Works in Newcastle. Science Museum blog: Stephenson’s Rocket returns to Newcastle
93 Robert Stephenson was 25 when Rocket was built. Science Museum blog: Stephenson’s Rocket returns to Newcastle
94 Rocket won the Rainhill Trials in October 1829, a public contest run by the Liverpool and Manchester Railway with £500 on offer. Science Museum blog: Stephenson’s Rocket returns to Newcastle
95 It beat three rivals, including an entry by John Ericsson. Encyclopaedia Britannica: Rocket
96 Britannica says Rocket reached 36 mph (58 km/h) for a short stretch. Encyclopaedia Britannica: Rocket
97 The Science Museum puts Rocket’s record at 35 mph, three times its design speed, with an average of 15 mph in the trials. Science Museum blog: Stephenson’s Rocket returns to Newcastle
98 Rocket went on to work on the Liverpool and Manchester, the world’s first main-line railway. Science Museum blog: Stephenson’s Rocket returns to Newcastle
99 Rocket’s big ideas were its multi-tube boiler and using exhaust steam to draw air through the firebox. Encyclopaedia Britannica: locomotive
100 Rocket had a single pair of driving wheels; later giants had as many as 14 coupled driving wheels. Encyclopaedia Britannica: locomotive
101 Union Pacific’s Big Boy locomotives weighed more than 600 short tons with the tender. Encyclopaedia Britannica: locomotive
102 A tank engine carries its fuel and water on its own frame; otherwise they ride behind in a separate wagon called the tender. Encyclopaedia Britannica: locomotive
103 Rocket became the fastest locomotive built up to that point. Science Museum blog: Stephenson’s Rocket returns to Newcastle
104 Britannica says railway steam became a commercial success with Rocket in 1829. Encyclopaedia Britannica: steam engine

Turbines and steamboats

105 Sir Charles Parsons invented the modern steam turbine in 1884, passing steam through rows of rotors that get bigger as the steam expands. Encyclopaedia Britannica: steam turbine
106 Parsons’s little ship Turbinia used a turbine with only spinning parts instead of pistons going up and down. Encyclopaedia Britannica: steam turbine
107 Navies put turbines in destroyers from about 1900 and in battleships from 1906, because they ran more smoothly. Encyclopaedia Britannica: steam turbine
108 Modern steam turbines reach efficiencies of 35 per cent or more. Encyclopaedia Britannica: steam turbine
109 People even tried turbine locomotives: one of the first was a Swedish engine built in 1921, but it came too late to beat diesel and electric trains. Encyclopaedia Britannica: steam turbine
110 The first practical steamboat was the tug Charlotte Dundas, built by William Symington and tried on the Forth and Clyde Canal in Scotland in 1802. Encyclopaedia Britannica: steam engine
111 Robert Fulton put a steam engine in a passenger boat in the United States in 1807. Encyclopaedia Britannica: steam engine
112 American steamboats began in 1787, when John Fitch made a successful trial run. Encyclopaedia Britannica: steamboat
113 Henry Shreve shaped the Mississippi steamboat: a high-pressure engine set high above the waterline on a hull as shallow as a barge’s. Encyclopaedia Britannica: steamboat

The big picture

114 Historian Arnold Toynbee dated Britain’s Industrial Revolution from 1760 to 1840. Encyclopaedia Britannica: Industrial Revolution
115 Steam engines powered locomotives, steamboats, steamships and factory machines. Encyclopaedia Britannica: Industrial Revolution