South Moluccan gunmen holding more than 160 people hostage in a train and school near here released four sick children from the school today and allowed food to be delivered to the train.

The cooperative gestures raised hopes for a peaceful outcome to the four-day-old siege, but none appeared near.

This morning, the terrorists occupying a train with 55 hostage passengers displayed one of the passengers, bound and gagged, outside the train for 15 minutes. This sudden show of force worried Dutch officials at the crisis center here.

Two psychiatrists, Dick Mulder and Henk Havinga, in charge of government phone contacts with the two teams of terrorists, spent the afternoon trying to impress on the guerrillas the need to ease the plight of the children.

The two have extensive experience in handling tense negotiations with terrorists.

Their tactics, say sources here, focus on building bonds of trust with the gunmen. The psychiatrists avoid harsh words but also avoid conveying signs of meekness. The aim is to let the terrorists know that each side needs the other to emerge from the situation without loss of life.

The psychiatrists glean every tidbit of information about the terrorists to draw a composite of their personality traits.

Dutch authorities have established that the terrorists, believed to number 15, are no older than 30. Some authorities say may still be teen-agers. Their moods fluctuate, alternately tense and relaxed. The crisis staft says a soothing yet assertive tone is best in dealing with them.

Buttressing that thesis are the traditional lines of Moluccan family life, in which parents play a far more dominant role than in Western culture.

Today, food supplies reached the train for the first time in 36 hours. Soup, meatballs, beans, and other hot meals prepared by the Red Cross, were brought to the train and school by unarmed policemen.

Tonight, in a display of concern by the royal family, Crown Princess Beatrix visited Bovensmilde to talk with parents keeping a vigil near the school where the children are being held hostage.