Complex sentence: The town of Fithian was a center for trading livestock and grain; it thrived when the Illinois Traction System (an interurban railroad) went through in 1903, and declined along with the ITS, especially during the Great Depression.
Split into simpler sentences: The town of Fithian was a center for trading livestock and grain. It thrived when the Illinois Traction System (an interurban railroad) went through in 1903, and decline along with the ITS, especially during the Great Depression.