TWICE IN recent days, the public has followed the dramatic stories of criminals who have taken innocent hostages. In both cases, impressive work was done by specially trained hostage negotiating teams, a relatively new phenomenon in law enforcement.

In Raleigh, N.C., a convicted Colombian narcotics dealer apparently shot and killed his sister aboard a New York-bound Amtrak train, then held her two small children hostage for almost three days. Local police did not have a trained negotiator who was fluent in Spanish, but the FBI dispatched Raymundo Arras, one of the federal agency's 300 trained negotiators. "This is Ray. I'm here to help you. How are the children?" he said, beginning a dialogue that lasted 33 hours. The younger baby died of dehydration during the siege, but Agent Arras was able to establish a relationship with Mr. Villabona that resulted in his releasing the other child and surrendering peacefully.

In New York, a prisoner with a long record of felony convictions overpowered a corrections officer while on a routine visit to a Brooklyn hospital and took five hospital employees hostage. He held out for 461/2 hours, and a police department negotiating team was on the scene from the beginning. Lt. Robert Louden spent the better part of the weekend "trying to build trust and confidence, trying to establish that we could treat each other as human beings and help each other out of this." All the hostages were released unharmed, and the gunman surrendered. Such person-to-person bridge-building, psychologists tell us, is just what's needed when dealing with a dangerous person who feels trapped. The objective is to set up voice communication -- through a wall or window or over the phone -- and to keep talking until the gunman has established a trusting relationship with at least one lawman. It takes time, but in almost every case it's far more sensible than attempting to rescue the hostages with force. In the 10 years the New York police have used trained negotiators, they have never lost a hostage. Neither has Washington's police department, which established this capability in a special operations division in the late '60s.

The frequency and randomness with which hostage-taking occurs makes everyone uneasy. The availability of trained police negotiators provides some reassurance that if the worst happens, sensible and effective help will be there.