The Taff Valley’s Locomotive

17 April 2016

So little is said about it that it almost seems like fantasy today, but the Taff Valley was at the cutting edge of the railways – before London, New York or Tokyo.  Hand in hand with the Industrial Revolution, which was led by this area, came the railways.

In 1802, Richard Trevithick, a Cornish genius, constructed a high-pressure steam engine to drive a hammer at the Pen-y-Darren Ironworks in Merthyr Tydfil. With the assistance of Rees Jones, an employee of the iron works and under the supervision of Samuel Homfray, the proprietor, he mounted the engine on wheels and turned it into a locomotive. In 1803, Trevithick sold the patents for his locomotives to Samuel Homfray.

Homfray was so impressed with Trevithick’s locomotive that he made a bet with another ironmaster, Richard Crawshay, for 500 guineas – probably the total wages for a few months of all the workers in the ironworks – that Trevithick’s steam locomotive could haul ten tons of iron along the Merthyr Tydfil tram road from Pen-y Darren to Abercynon, a distance of nearly ten miles. Amid great interest from the public, on 21st February 1804 it successfully carried ten tons of iron, 5 wagons and 70 men the full distance in 4 hours and 5 minutes, which was an average speed of approximately 2.4 mph. As well as Homfray, Crawshay and the passengers, other witnesses included Mr. Giddy, a respected patron of Trevithick and an engineer from the government.

The bet was won. Despite many people’s doubts, it had been shown that, provided that the gradient was sufficiently gentle, it was possible to successfully haul heavy carriages along a smooth iron road using the weight alone of a suitably heavy and powerful steam locomotive. Trevithick’s was probably the first to carry out this feat.  However some of the short cast iron plates of the tram road broke under the locomotive as they were intended only to support the lighter axle load of horse-drawn wagons and so the tram road returned to horse power after the initial test run.

Homfray was pleased he had won his bet but the engine was then placed on blocks and reverted to its original stationary job of driving hammers.

Today in Merthyr Tydfil, behind the monument to Trevithick’s locomotive is a stone wall, which is the only remainder of the former boundary wall of Homfray’s Pen-y-Darren House.

A full-scale working reconstruction of the Pen-y-Darren locomotive was commissioned in 1981 and is on display at  the National Waterfront Museum in Swansea. Several times a year it is run on a short length of rail outside the museum.  Somehow we think that if this was in other parts of the world much more fuss would be made of it.

Paul Barrett
Title image credit: Hugh Llewelyn