Then the Chinese actor cried: 'I have a right to reality!'

''I have the right to live! I have the right to love!'' cries the young hero of an experimental play being performed before packed houses here night after night.

''Emergency Signal,'' by a new playwright, Gao Xingjian, takes up the conflicting claims of love, comradeship, and duty among the young people of today. This is the first play in China to be performed in ''little theater,'' or workshop style. There is no stage, properly speaking, and actors perform without makeup. At the end of the performance the entire audience of about 300 is invited to participate in a discussion of the play and of the problems it raises.

In a communist society, the first purpose of a play is not to entertain but to educate. But young people in China, like their contemporaries all over the world, are tired of sermonizing. They are quick to detect hypocrisy and cant, and many of them say they find little in the theaters and cinemas or on television that they really care to see.

''Emergency Signal'' is different. While good ultimately triumphs over evil, the characters are all believable, and there is no overt preaching. The entire action - two hours without intermissions - takes place on the caboose of a freight train where two young men and a girl accidentally meet.

''Trumpet'' is an apprentice crew chief on the train. ''Blackie'' comes to hitch a ride, as does the girl, ''Honeybee.'' Another hitchhiker, an acquaintance of Blackie's, is a bandit. The train's veteran crew chief stands for the voice of duty and of experience in what turns out to be a contest for Blackie's conscience and soul.

The gruff crew chief had to work 10 years to earn his badge. But Trumpet will take only a couple of years, because his father is a bureau director in the state railway system. To Trumpet, working on the train is just a job. His real joy in living comes from playing his trumpet.

Blackie is unemployed. He could have been given his father's slot on the railway when the latter retired, but he gave up that prized right to his sister. (In China, where unemployment is an increasingly severe problem, parents may hand on their slots - not of course their specific jobs - to a son or a daughter. That is often the only way that son or daughter will get a decent job.)

Blackie and Trumpet are both in love with Honeybee, who prefers Blackie. But Honeybee's father will not hear of her marrying an unemployed, destitute youth. Blackie feels caught in a web not of his own making. His desperate assertion of his right to live and to love is made at this point.

Eventually Blackie falls in with a smooth-talking villain who persuades him that a single ''easy'' train robbery will net him all the money he needs. His job, and the villain's, is just to keep the train crew occupied while an accomplice loots a freight car and hurls out the booty. In the end, duty prevails and Blackie is wounded even as he knifes the villain.

On the night this correspondent saw the play, the audience divided in little clumps surrounding each actor after the play, arguing about specific points. Sometimes the discussion has gone on till midnight.

The veteran actor Lin Liankun, who plays the train chief, said he was exhilarated by the intimacy achieved by being within a couple of feet of the audience. Shang Lijun (Honeybee) agreed, as did Cung Lin (Trumpet). Despite the subtleties and symbolism of traditional theater as exemplified in Peking opera, modern Chinese audiences are uncomfortable with too sharp a departure from realism. In this play, there were no transitions from speech to mime or dance, none of the intellectual demands one associates, for instance, with Brecht.

Perhaps this is because in today's China alienation and ambiguity have little dramatic currency. Playwrights may take up problems but these have to do with how the individual is to fit into society, how society is to deliver on the promises it has made, how ''contradictions'' are to be dealt with even if they cannot be overcome.

Still, ''Emergency Signal'' is a bold departure from the conventional for the Peking People's Art Theater, which during its 30-year history has consistently explored how to meld flamboyant Chinese dramatic forms with the Stanislavsky tradition of the Moscow Art Theater. The third-floor banquet hall where ''Emergency Signal'' is being staged is likely to be the venue for more exciting experiments to come.