THE DEMOCRATIC PARTY has ended weeks of haggling over details to formally name Chicago the site of its 1996 national presidential nominating convention, the committee said. . . . A FREIGHT TRAIN on Tuesday slammed into a car at a crossing in Douglas, Wyo., killing the five teens in the car. . . . TEMPERATURES in Tokyo soared to a record 101 degrees on Wednesday, and meteorological officials warned residents a cloud of sweltering weather was likely to hover over Japan throughout the month. . . . NORTH KOREA'S export-import volume dropped 2.4 percent in 1993 from a year earlier to $2.75 billion, caused by a deteriorating economy and suspicions over its nuclear weapons program, a government-subsidized trade organization said.