The American inventor Oliver Evans developed the concept for a high pressure steam engine in 1794. Evans steam engine was a high pressure engine, which was a vast improvement in power over Watts low pressure engines. In high pressure steam engines, steam pressure is used to press a piston down, as opposed to pulling down in a low pressure system, with the low pressure created when the steam cools and contracts in volume. Evans sent his plans to England for scientific review, and many feel that their teachings were read and understood by Englishman Richard Trevilthick.
Trevilthick first built a steam engine to operate a water pump in Cormish mines, and later built a locomotive in 1807 (the first in the world) and still later an automobile.