It is widely known that
Richard Trevithick built
the first railway locomotive;
and many people still imagine that
it was the Penydarren engine of 1804.
In fact he made one in 1802‑3 for the Coalbrookdale Company in Shropshire,
the first firm to take an interest in his high pressure engine after the patent of 1802,
though it is far from certain whether this engine actually ran.