Baltimore County police released the name yesterday of the woman who was killed by a train Sunday night in Rosedale, but they said they were still trying to confirm the identity of the man who died with her. Yvonne Lou O'Neil, 44, of the 800 block of Creek Road in Essex and the man were killed by the southbound, 135-car CSX train about 10 p.m. Sunday while lying between the rails near the Schaeffer Lane crossing, said Bill Toohey, a police spokesman. Police believe they know the man's name but need to confirm it, possibly through dental records or DNA tests, he said. Although the incident appeared to be a double suicide, police are continuing their investigation into how the two came to be on the tracks, Toohey said. "The deaths are being investigated as possible suicides, but that is tentative based on the outcome of the autopsy," he said.