I recorded Dan Snow’s Locomotion: a history of the railway to see what he had to say about Richard Trevithick, the Cornish mining engineer who built the first working steam locomotives one of which carried 50 tons of iron and 70 men nearly ten miles in 1804. But there was no mention of him. Episode one lurched from a stationary steam engine which pulled a cable to Stephenson’s Rocket in 1830. Nothing in between. And everything that went right in that quarter of a century, every innovation was attributed to Stephenson and his son Robert, who was a mere lad when Trevithick visited them in the North East. I spun back and forth to find out if there was an account of the radical change in technology which made the steam locomotive possible. Nothing. Just a vague reference to steam engines evolving. I sat there thinking: this programme is not on the rails. Everything about it was wrong. Where on earth did Snow and his researchers go for their information? The history of steam railways and the steam engine is recounted in a huge number of books and the basics are not in dispute.
Snow did not explain that the early steam engines which pumped water from mines and were refined by James Watt and Matthew Boulton and later drove machinery were “atmospheric engines”. Their power was not generated by expanding steam directly but by air pressure: a cylinder was filled with steam which drove out the air creating a vacuum in which atmospheric pressure drove down a piston. Watt’s innovations made them much more efficient in the use of coal and therefore more widely available.
Cornish tin miners resented the tariff they had to pay for the use of the Boulton-Watt engines and sought a way round the patent. It was this that inspired Trevithick to construct an entirely new kind of engine which was powered by expanding steam. His first Puffing Devil was a road vehicle that ran on Christmas Eve 1801. It burned down, but he built others, one of which exploded in London killing some of his men. Because what he called “ strong steam” was dangerous, Watt was dead against it and reviled Trevithick for his invention.
However, these new engines were more compact than the stationary atmospheric engines and were more suitable for powering a vehicle. Trevithick was thwarted because the existing railway tracks were laid for horse drawn wagons and were not strong enough to carry a locomotive. Wrought iron rails,which were first introduced in the 1820s, solved the problem, by which time Trevithick was otherwise engaged in silver mines in Peru. He was invited to go there because atmospheric engines would not operate at very high altitudes whereas his "strong steam" engines did.
In the Snow version of railway history the impulse to create this new form of transport came from the big cotton importers and manufacturers and it all kicked off in 1830. No mention of George Stephenson’s run on a section of the Stockton to Darlington line five years earlier. No mention of the fact that Stephenson was asked to look at the emerging locomotive technology by mine owners concerned about the rise in the price of horse power during the Napoleonic Wars.
Did Snow and his team know all this but decided that it would be too much for a popular audience to take?