BY CHHUN SUN, MARIA ST. LOUIS-SANCHEZ AND STEPHEN HOBBS The Gazette -Officials spent Monday investigating the cause of a railroad train derailment near the Martin Drake Power Plant in Colorado Springs and trying to quell concerns about the white chemical that spilled from the cars. Mounds of ammonium sulfate pellets dumped from the derailed cars remained at the site of a 13-car Burlington Northern Santa Fe Railway train that derailed at 10:35 p.m.