Penydarren Locomotive (1804): Trevithick's First Railway Run

The Penydarren locomotive, built by the Cornish engineer Richard Trevithick, made the world’s first recorded railway journey by a steam locomotive on 21 February 1804. It hauled about 10 tons of iron and some 70 passengers along a horse-worked tramroad from the Penydarren Ironworks in Merthyr Tydfil, South Wales, to the canal at Abercynon. The run settled a wager between two ironmasters and showed that steam could move loads on rails, two decades before the first public steam railway.

Background: high-pressure steam

Late eighteenth-century steam engines followed the design of James Watt’s steam engine. They worked at little more than atmospheric pressure, used a separate condenser and were large and heavy, suited to pumping mines or driving mills rather than moving themselves. Watt regarded high-pressure steam as dangerous and opposed its use.

Richard Trevithick (1771–1833), the son of a Cornish mine captain, took the opposite view. From the late 1790s he built engines using “strong steam” at much higher pressure, exhausting it into the air instead of condensing it. These engines were small and light enough to be mobile. On Christmas Eve 1801 his road carriage, later nicknamed the “Puffing Devil”, carried passengers up a hill at Camborne in Cornwall, and in 1803 he ran a steam carriage in London.

He also designed a rail locomotive for the Coalbrookdale Company in Shropshire around 1802–1803, close to the Iron Bridge. Surviving drawings show the design, but it is unclear whether it ever ran.

The wager at Merthyr Tydfil

Merthyr Tydfil was then the largest iron-making centre in Wales. Its ironworks shipped iron to Cardiff along the Glamorganshire Canal, and the Merthyr Tramroad, opened in 1802, carried it from the works to the canal at Abercynon in horse-drawn wagons. The tramroad used L-shaped cast-iron plates on stone blocks, with plain-wheeled wagons running inside the flanges.

Samuel Homfray, owner of the Penydarren Ironworks, had bought a share in Trevithick’s patent and commissioned a high-pressure engine. According to the traditional account, Homfray bet his rival Richard Crawshay of the Cyfarthfa Ironworks 500 guineas that a steam engine could haul 10 tons of iron the length of the tramroad. Trevithick mounted an engine on wheels to win the bet.

The journey of 21 February 1804

The locomotive had a single horizontal cylinder set inside the boiler, a large flywheel and gears driving the wheels. Exhaust steam was turned up the chimney, which Trevithick noticed increased the draught on the fire, an effect later exploited by the blastpipe.

On 21 February 1804 the engine hauled five wagons carrying about 10 tons of iron, with around 70 men riding on them, from Penydarren to Abercynon, about 9.75 miles (16 km). The journey took 4 hours and 5 minutes. Much of that time was spent stopping to cut down overhanging branches and move rocks from the track; Trevithick reported that the engine ran at nearly 5 miles per hour when moving.

Trevithick described the trials in letters to his friend and patron Davies Giddy (later Davies Gilbert), a Cornish scientist and politician. Accounts differ on whether the return trip was made under steam and whether Crawshay ever paid the wager.

Why it was not repeated

The engine worked, but the track did not. Weighing about 5 tons, the locomotive cracked the brittle cast-iron tramplates, which had been designed for horse-drawn wagons. After a few more runs the engine was taken off the rails and used as a stationary engine, driving machinery at the ironworks. Horses continued to work the tramroad for decades.

Trevithick built a locomotive for the Wylam colliery in Northumberland in 1805, but it too proved too heavy for the wooden track. In 1808 he ran Catch Me Who Can on a circular track near Euston Square in London, charging the public for rides, until a broken rail derailed it and the show closed.

Trevithick’s other ventures

Trevithick’s restless inventiveness took him in many directions after 1804. His compact high-pressure engines were sold for pumping water from mines, winding ore and driving machinery, and they became a familiar sight in Cornwall and South Wales. In 1807–1808 he worked on an early attempt to tunnel under the Thames for the Thames Archway Company, driving a small pilot heading far under the river before flooding stopped the work. He also experimented with iron tanks for ships and with steam-powered threshing.

Many of these schemes were technically promising but financially disastrous. Trevithick was a gifted practical engineer but a poor businessman, and he rarely stayed with one project long enough to make it pay. Others, including George Stephenson, would turn locomotive engineering into a reliable industry.

Myths and facts

Myth: George Stephenson built the first locomotive. Stephenson’s first engine, Blücher, ran in 1814, ten years after Penydarren. His fame rests on making locomotives and railways practical, not on inventing them.

Myth: the Penydarren engine was a failure. It did exactly what it was meant to do on 21 February 1804. The problem lay in track designed for horses, not in the engine itself.

Myth: the details of the wager are certain. The 500-guinea bet comes from later family and local tradition. Trevithick’s own letters confirm the trials and the load hauled, but say little about the bet.

Key people

• Richard Trevithick (1771–1833): Cornish engineer who designed and drove the locomotive.
• Samuel Homfray (1762–1822): ironmaster of Penydarren who financed the engine and made the wager.
• Richard Crawshay (1739–1810): owner of the Cyfarthfa Ironworks, the other party to the bet.
• Davies Giddy (1767–1839): Trevithick’s patron, whose correspondence records the trials.

Consequences

The Penydarren run proved that a steam locomotive with smooth wheels could grip smooth rails and haul a heavy load, a point some engineers doubted. It also showed the need for stronger track. As wrought-iron and better cast-iron rails appeared, colliery engineers in north-east England took up the idea. Matthew Murray and John Blenkinsop’s rack locomotives began work on the Middleton Railway near Leeds in 1812, William Hedley’s Puffing Billy ran at Wylam from about 1813, and George Stephenson built Blücher for Killingworth in 1814.

These experiments led directly to the Stockton and Darlington Railway in 1825 and the Rainhill Trials of 1829.

Trevithick himself moved on. In 1816 he sailed to Peru to install engines in silver mines, and he spent years in South and Central America amid war and hardship. He returned to England in 1827 with little money and died in Dartford, Kent, on 22 April 1833.

Legacy

Trevithick’s high-pressure engine, not Watt’s low-pressure design, became the basis of every steam locomotive. Wales commemorates the 1804 run with a monument in Merthyr Tydfil and a replica locomotive, built around 1980–1981 and displayed at the National Waterfront Museum in Swansea. In 2004 the replica ran on a short track in Merthyr for the bicentenary.

By the numbers

Timeline

• 1771, 13 April: Richard Trevithick is born at Tregajorran, Cornwall.
• 1801, 24 December: Trevithick’s steam road carriage climbs Camborne Hill.
• 1802: The Merthyr Tramroad opens for horse-drawn traffic.
• 1802–1803: Trevithick designs a rail locomotive for Coalbrookdale.
• 1804, 21 February: The Penydarren locomotive hauls iron and passengers to Abercynon.
• 1808: Catch Me Who Can gives public rides in London.
• 1816: Trevithick leaves for Peru.
• 1833, 22 April: Trevithick dies in Dartford, Kent.

Why it matters

The Penydarren run was the first proof that a steam locomotive could do useful work on rails. Though the track failed, the idea survived, and within a generation steam railways began to transform transport across the world.