Father Gets Off Train, Leaving Children Behind Around 4 a.m. last Saturday, aboard a commuter train sidling through Long Island, a faint whimpering began to fill the sixth car somewhere east of Wyandanch. Two children, a 3-year-old boy and a 14-month-old girl, sat in a double stroller, their diapers soaked through their clothes. A man had been with them earlier, witnesses recalled, pushing the stroller into the car at the Jamaica station. Crew members checked the bathrooms for him. They ducked into neighboring cars. "No parent," said Sgt. Gary Rinaldi of the Metropolitan Transportation Authority Police, who met the Long Island Rail Road train at the Ronkonkoma station around 4:20 a.m. They could see they were on their own. It is a pastime for commuters on the transit system to leave something behind - a punched ticket, lunch detritus, or, less intentionally, a wallet or a phone. But transit officials said that last weekend's episode appeared to be without precedent: two young children, brought aboard for an early morning ride and then stranded - at least briefly - without anyone noticing. Crew members stayed with the children until the train reached Ronkonkoma, trying gamely to entertain them. "They were actually playing with the kids when we pulled up," Sergeant Rinaldi said. Conductors usually have little trinkets here and there. He was making noises with the hole puncher. A passenger hurried home from the station to get a diaper, Sergeant Rinaldi recalled, before emergency personnel took the children to Brookhaven Memorial Hospital Medical Center. They "appeared to be in good health," Sergeant Rinaldi said. The police soon learned that the man identified as the children's father had gotten off at Hicksville. It was unclear why. A spokesman for the authority said the man seemed to have become disoriented and appeared to officers to be intoxicated. After calling 911 himself to report that he had left the children, according to Sergeant Rinaldi, the man told officers that he had fallen asleep on the train. The authority asked that the man's name be withheld to protect the children's privacy. He was charged with two counts of endangering the welfare of a child. On Friday, he pleaded guilty in district court in Nassau County, a spokesman for the district attorney's office said. He was sentenced to five months in jail. Sergeant Rinaldi said the man had 22 prior arrests in New York since 1982, for offenses that included violent crimes, sex abuse and attempted robbery. He added that the children's mother had an order of protection against him, barring the man from coming into contact with her or the children. But when contacted after the children were found on Saturday, according to the police, the woman said she was aware that they had been with their father, though she did not know where he had taken them. Child protective services have become involved in the case, Sergeant Rinaldi said, but it was unclear in whose care the children would remain.