Gusta Stromer was 16 when she, her mother, and her three sisters were sent to Belzec, a death camp in Poland. As the train charged toward the crematorium, two boys pried open a tiny window and jumped out. ''You jump too,'' her mother urged her. She landed in a cabbage field and never saw her mother again.
''You wake me up in the middle of the night and it's with me,'' said Ms. Stromer, a tall, strong-jawed woman with a thick Polish accent and clear blue eyes.
But until yesterday, Ms. Stromer had never spoken in public about her parents' deaths or her harrowing journeys through Poland with her surviving sister.
What finally got to Ms. Stromer were those who denied history.
''When I heard there are people who deny the Holocaust, I can't tell you what I felt,'' she said as her son drove her from her Upper West Side apartment to speak about her experiences at the Bruriah School, a Jewish school for girls in Elizabeth, N.J., that her granddaughter Esther Malka Stromer, 15, attends.
''Anytime I would go talk to a denier,'' she said. ''I'd say: 'It never happened? What happened to my neighbors, my parents, my town?' ''
Her fellow guest speaker, Thomas Martinez, is a former white supremacist who now speaks to Jewish groups about his past and his change of heart, after years of disbelieving the Holocaust.
After hearing Ms. Stromer speak, Mr. Martinez approached her.
''I want to shake your hand,'' he said.
''I wish I would've known you 25 years ago. I never even heard about the Holocaust back then.'' Nodding solemnly, Ms. Stromer held out her hand.
Ivy Barsky, director of education at the Museum of Jewish Heritage in Lower Manhattan, said that while some survivors had been speaking out for 50 years, many have only come forth recently. ''They realize that in 15 years a lot of them aren't going to be here, and they feel a need for their stories to be told,'' she said.
Encouraging them to do so is the focus of a daylong workshop given twice a year at the museum. The program began in 1997, when the museum opened. ''We started getting phone calls asking, 'Do you have survivors who could go out and speak?' '' Ms. Barsky said. Beginning with just a few, the museum's speakers bureau now has 90 people who tell their stories at local schools and synagogues on and around May 2, Yom Hashoah, or Holocaust Remembrance Day.
During the workshops, teachers discuss retrieving memory, tailoring presentations to different audiences and how to convey experiences that seem too haunting to translate into narrative.
They tell speakers not to give a comprehensive history of the Holocaust, but simply to keep it personal. ''It's important to let them know that they are only an expert on their own stories,'' Ms. Barsky said.
Lisa Lipkin, a professional storyteller who was a guest speaker at a workshop in March, said the classes were not group therapy, but rather a way to help personalize memories.
''If they say, 'My mother was beautiful,' I say, 'Oh, do you mean that she had red curls that fell to her shoulders, or such bright green eyes that everyone stopped to stare at her?' '' she said.
Eliciting the sounds and smells of vanished lives ''can be like pulling teeth,'' said Ms. Lipkin, who is the daughter of a survivor.
''I had one woman,'' she said, ''who said, 'I have no memories, I have nothing.' But then suddenly she remembered her mother's pound cake and it became a metaphor for this beautiful life they had.''
While Ms. Stromer said that hearing about the deniers wiped away her fears of speaking out, others need more nudging.
Until joining the speakers bureau, Bronia Brandman, a retired schoolteacher, had not spoken about her experiences even to her closest family members.
''I never told my children that I had a brother or sister or anything,'' said Ms. Brandman, 69, who spent two years in Auschwitz and whose parents, brother and three sisters were killed by the Nazis.
Ms. Brandman said that she originally went to the museum to train as a gallery educator, but that a more experienced speaker, Norbert Friedman, coaxed her into telling her tale.
''He felt that I owed it,'' she said. ''Also I realized that this is going to take me over if I don't speak.''
Mr. Friedman recalled Ms. Brandman's first speaking engagement three years ago at New Hyde Park (N.Y.) Memorial High School.
''She was petrified,'' he said. ''But then when she started to speak, you should have seen the faces of the girls. I drove her home and she was trembling, but she was like a bird let out of a cage.''
Now one of the speakers bureau success stories, Ms. Brandman sat in the balcony at the Flatbush Park Jewish Center synagogue Monday night, clutching a stack of index cards.
Dressed in an olive-colored suit with a delicate flower brooch, Ms. Brandman whispered, ''I never feel ready.''
But once on stage, her voice did not waver.
The room fell silent as the tiny, fine-boned woman told of smuggling food to her family, of seeing her parents waiting to be shot, of watching her sisters walk to the gas chamber.
''Twenty-six years later,'' she concluded, ''I went to Israel and laughed for the first time. Five years after that I found myself singing. But nothing has induced me to cry. And I deeply want to cry. I want to howl and howl and howl, to infinity.''
For this audience, comprised of fellow survivors and their children, it was not the details that impressed them so much as Ms. Brandman's ability to speak of them. Women crowded around, some in tears, to kiss and thank her.
''My father was never able to talk about it,'' one woman said.
''I just want to tell you how much I appreciate that you could.''
Ms. Brandman still doesn't talk to her family much about her experiences, although she now shows them her writing on the subject.
But, she said, public speaking has become a form of self-preservation, relieving long-simmering pressures and helping her, for the first time, to evoke her mother's face.
It has also helped reconnect her with a world that once seemed to have abandoned her.
''You feel you weren't talking to people who were indifferent, gloating even,'' she said. ''There's always this fear that maybe somebody's gloating. It did an awful lot for my restoration of faith in humanity.''
But she said she still feels mixed about speaking to schoolchildren. ''How do you tell young people about this?'' Ms. Brandman asked. ''It pains me to expose children to such barbarity. On the other hand, how could you not tell?''
Correction: May 8, 2000
A picture caption on Wednesday about Gusta Stromer, who recounted her Holocaust experience at the Museum of Jewish Heritage in Lower Manhattan, referred to her incorrectly. She was not her family's only survivor; her sister Rochelle jumped with her from a train headed for the Belzec death camp in Poland and lived. Their mother and two other sisters died