Complex sentence: Cornwell served as the president of the Hampshire Southern Railroad which was constructed under his leadership, beginning in June 1909, and he continued to operate it until 1911 when it was purchased by the Moorefield and Virginia Railroad Company.
Split into simpler sentences: Cornwell served as the president of the Hampshire Southern Railroad which was constructed under his leadership, beginning in June 1909. The Hampshire Southern Railroad Company continued to operate this rail line until 1911, when it was purchased by the Moorefield and Virginia Railroad Company.