who built first steam locomotive
Readers might wish to consult David Fry's Danger Ahead! -- Historic Railway Accidents (UK website) [ GPL ]. The first self-propelling steam engine or steam locomotive made its outing on 13 February 1804 at the Pen-y-Darren ironworks. The machine was designed by Richard Trevithick. The engine was able to pull a load of 15 tons at a speed of about 5 mph. However, adhesion was a problem (iron wheels on iron rails = slipping).