Simplify the following text for a Grade 3 native English-speaking person.
Original: George Stephenson ( 9 June 1781 -- 12 August 1848 ) was an English civil engineer and mechanical engineer who built the first public railway line in the world to use steam locomotives .
Simplified: George Stephenson was born on the 9 June 1781 . He died on the 12 August 1848 .