Authorities now know the cause of Sunday’s train derailment in Boone. Union Pacific spokesman John Bromley says seven cars of an east-bound train derailed on an overpass at about four o’clock Sunday morning, spilling four-hundred tons of coal onto the city street below. Bromley says it’s an expensive clean-up..and could run 270-thousand dollars. Bromley says the viaduct has been inspected and remains structurally-sound. The street remains closed, creating traffic woes in Boone as it’s the only north/south street in town which allows motorists to escape stoppages because of crossing trains.