Kristen Lahmeyer, 19, left her home in Winnetka, Ill., at around 6:30 p.m. and stepped onto a nearby train track, where she was hit by a southbound commuter train, said Winnetka deputy police Chief Eric Bennett.
The conductor saw Lahmeyer but could not stop the 60 mph train in time to prevent a collision, police said.
Lahmeyer's death was instantaneous upon impact.
Lahmeyer had been taking a break from school for the fall semester, living with her mother at their home in Winnetka and working as an aerobics instructor.
Friends described her as a friendly, cheerful and kind person with a "contagious laugh" and "boundless creativity."
"I talked to her on Tuesday," said sophomore Mojdeh Rezaeipour, a friend who took several classes with Lahmeyer last year. "It's just such a shock."
Rezaeipour said she had no idea that Lahmeyer suffered from depression until this summer.
"She was taking medication," Rezaeipour said. "But she said that she was just taking a semester off and she was better now."
Connie J. Beckerman, Lahmeyer's mother, said her daughter had been looking forward to returning to Berkeley in the spring and seeing her friends again.
"I always called her my heart-full- of-love girl; that's how I can describe her," Beckerman said. "More than anything, she wanted to make the world a better place. She was a deeply caring person."
According to her mother, Lahmeyer was "very artistic" and interested in drawing, painting, music and the arts.
Lahmeyer entered UC Berkeley planning to study architecture, but decided to switch to an art major after a year, Beckerman said.
Her friends said they were surprised and deeply saddened by her death.
"I don't think she ever knew how many of us loved her or just how much," said sophomore Natasha Streit, who shared a La Loma suite at the Foothill residence halls with Lahmeyer last year. "We all hope she finds the peace and happiness she was looking for."
Lahmeyer was born on March 13, 1986 in Chicago, Ill. She attended New Trier High School, where she was an honors student, sang in the concert choir and played water polo.
Lahmeyer is survived by her mother, her father Henry Lahmeyer, one sister and two stepsiblings.
A memorial service will be held at 4 p.m. Friday, Nov. 11 at the Winnetka Congregational Church.