The Chester Secondary is an active railroad line in the U.S. states of Pennsylvania and Delaware. The line is operated by Conrail Shared Assets Operations, which serves as contract local carrier and switching company for both CSX Transportation and the Norfolk Southern Railway. The line runs from Philadelphia to Claymont, Delaware, a distance of 14.9 miles (24.0 km). It traverses the namesake Stoney Creek, Chester Creek, Ridley Creek, Crum Creek and Darby Creek near their mouths along the shore of the Delaware River.