About 4:25 a.m. on May 16, 1976, the locomotive and 27 cars of Chicago and North Western freight train No. 242 derailed as they moved eastward on a 154' to 215' compound curve just west of Glen Ellyn, Illinois. Another CNW freight train, No. 380, was moving eastward on an adjacent track at the time and struck the derailed cars of No. 242; the locomotive and nine cars of train No. 380 derailed. The tank-head of train No. 380's fifth car was punctured during the derailment by the coupler of an adjacent car; this released anhydrous ammonia into the atmosphere. Fourteen persons were injured as a result of the derailment and release of the ammonia. Damage from the accident was estimated to be $1,914,600.