Complex sentence: Crowds waited for the train to cross the Stockton to Yarm turnpike and approaching Stockton it gained speed and reached, when a man clinging on the outside of waggon fell off and his foot was crushed by the following coach.
Split into simpler sentences: Crowds waited for the train to cross the Stockton to Yarm turnpike. It gained speed as it approaching Stockton, reaching, when a man clinging on the outside of waggon fell off and his foot was crushed by the following coach.