Complex sentence: His success as a canal contractor brought him into contact with a number of influential businessmen and politicians, including Hincks, and into the field of railway construction and railway politics, where Americans soon achieved a commanding presence.
Split into simpler sentences: His success as a canal contractor brought him into contact with a number of influential businessmen and politicians, including Hincks. It also brought him into the field of railway construction and railway politics, where Americans soon achieved a commanding presence.