HANNA, Ind. --An investigation is underway into a truck crash that killed three teenagers over the weekend. It happened Saturday morning at a train crossing in Hanna, 16 miles southeast of Valparaiso. The crossing was apparently marked with a stop sign but had no flashing lights. The teenagers may not have heard or seen the train approaching before it smashed into their vehicle. Two teenagers died instantly and a third died at the hospital. All of them attended the same high school.