Complex sentence: Frederick Swanwick (1810-1885) was a civil engineer who assisted George and Robert Stephenson and was responsible for much of the work on railways in the North and Midlands of England, particularly the Whitby and Pickering Railway and the North Midland Railway.
Split into simpler sentences: Frederick Swanwick (1810--1885) was an English civil engineer who assisted George and Robert Stephenson. He was responsible for much of the work on railways in the North and Midlands of England, particularly the Whitby and Pickering Railway and the North Midland Railway.