On 28 Oct, 13:32, Jules
wrote:

Yes, that's what I suspected - and particularly as his early efforts
seemed attached to the coal mining industry,

Trevithick was one of the few who _wasn't_ attached to coal mining.
His "Newcastle" locomotive, for the Wylam colliery, was something like
his sixth engine (we don't know how many stationary engine he built
beforehand). Before that he'd come from Cornwall via Wales, with
detours through road transport and exhibitions. The industries he was
more closely associated with were metal ore mining in Cornwall and
iron-founding in Wales.

As Cornwall had no coal available and little wood at most of the mine
locations the large number of stationary pumping engines there were
dependent on imported fuel at greater cost. This encourages a more
careful approach to efficiency and innovation than in the coalfields
of Dudley or Tyneside. Many innovations, like Woolf's compounding, and
the whole Cornish engine approach itself (slow, huge, but surprisingly
efficient, right into the 20th century) were driven by the price of
fuel in Cornwall.