BY CHHUN SUN chhun.sun@gazette.com -Railway crews and road officials on Tuesday continued cleanup from the train derailment near the Martin Drake Power Plant and residential area in Colorado Springs Seven Burlington Northern Santa Fe Railway cars spilled mounds of ammonium sulfate at 10:35 p.m. Sunday. The chemical that spilled is not harmful and is commonly used for lawn treatment and can be purchased at home improvement stores, the Colorado Springs fire department said. BNSF Railway spokesperson Joe Sloan said the cleanup effort is expected to continue Wednesday. Workers repaired the tracks and removed ammonium sulfate from the ground on Tuesday, Sloan said.