first_imgCrews are trying to determine how quickly crude oil leaking from derailed railroad tanker cars near Doon, Iowa will reach cities downstream.One or more of 31 tanker cars on the derailed train is leaking into floodwaters surrounding the tracks near Doon in Sioux County.The train derailed around 4:30 a.m. Friday.It’s not yet clear how many tankers are leaking or how much oil has escaped.Ken Hessenius with the Iowa Natural Resources Department says his crews will try to determine how fast the oil is being carried downstream by the rain-swollen Little Rock River.It joins the Rock River a few hundreds yard west, which courses south into the Big Sioux River.That empties into the Missouri River at Sioux City.He says towns supplied by shallow wells near the Rock River have been alerted about possible contamination.Photos by Sioux County Sheriff’s Drone——————————————————–Some residents in the Sioux County town of Doon have been evacuated following a train derailment that caused a crude oil leak.The Sioux County Sheriff’s Office says residents living along a rural road south of Doon have left their homes.Sheriff Stewart Vander Stoep in neighboring Lyon County says the train derailed between 5 and 5:30 a.m. Friday just south of Doon.He says it’s unclear how much oil has leaked.It’s also unclear how many cars derailed and what caused the derailment.Floodwater along the Little Rock River is running over a road north of the track.Evacuations have occurred downstream at Rock Valley, where the Rock River is expected to crest later Friday.APlast_img read more