Federal and state agencies are still trying to determine what caused a Wednesday afternoon CSX train derailment in downtown Lynchburg. Bill Hayden of the Virginia Department of Environmental Quality says one major question is the impact on the James River. City officials estimate that roughly 50,000 gallons of oil are missing from the tanker cars, but they can’t be sure how much of it burned up, and how much wound up in the James. The National Transportation Safety Board is also investigating the incident.