When was the first locomotive engine built?

In 1813, George Stephenson became aware that William Hedley and Timothy Hackworth were designing a locomotive for the Wylam coal mine. So at the age of twenty, George Stephenson began the construction of his first locomotive. It should be noted that at this time in history, every part of the engine had to be made by hand, and hammered into shape just like a horseshoe. John Thorswall, a coal mine blacksmith, was George Stephenson's main assistant.