YILAN, Taiwan - Taiwan President Tsai Ing-wen offered words of comfort and encouragement on Monday as she met relatives of the 18 dead and 187 injured after a train derailed in the island's northeast, its worst such disaster in more than three decades.Four carriages overturned in Sunday's crash in Yilan county near the coast on a route frequented by sightseers after all eight cars of a train carrying 366 passengers left the tracks on a bend near a railway station, officials said."We are really sorry ... you have to stay strong," Tsai told Chen Yu-Chan, 41, whose only daughter, a seventh grader, was killed."We will do everything we can," she said to another person, who was sobbing bitterly during Tsai's visit to a county hospital.An American was among those injured in the disaster, which the official Central News Agency said was the island's deadliest rail tragedy since a 1981 collision in northern Taiwan that killed 30 people.Train services resumed early on Monday, after all the derailed carriages had been moved to one side of the tracks. It was unclear what caused the crash, and authorities said they had launched an investigation to find out."The train was in pretty good condition," Lu Chieh-Shen, deputy chief of the railway administration, told a news conference late on Sunday.Hundreds of rescuers and military personnel worked through the night, using spotlights to search the wreckage for survivors, as ambulances waited nearby to take the injured to hospital.Some rescue workers gave first aid to the injured, while others used cranes to lift some of the battered cars sprawled in a zigzag near the tracks."The train was going very fast. I thought to myself: Why was it not slowing down on a curve?" said Henry Tseng, who was riding one of the overturned carriages and suffered eye injuries."I hit a wall when the car started to flip," added the 30-year-old Tseng. "Around five to six people were thrown out of the carriage door...There's no time to think what happened. Everyone was in a rush to get out."On Monday, Chen Tai-liang, whose niece, a seventh grader, was killed, said, "This is something that is not supposed to happen when taking a train." "Why did it happen?" she asked, after speaking to Tsai.