PHOTOS: Three semis went up in flames in south suburban Alsip early Wednesday morning. Firefighters responded to a report of a truck fire near 123rd Street and Lombard Avenue around 4:45 a.m. When they arrived, they found three semis fully engulfed by flames. Power lines sparked as firefighters worked to extinguish the blaze. Investigators are working to figure out what caused the big rigs to catch fire.