The daycare worker from Stamford, Connecticut, had been in the city visiting a cousin when the accident happened.
Malaysia Goodson was found unconscious and unresponsive at the bottom of the southbound 7th Avenue B, D and E station stairs just before 8 p.m. She was taken to the Mount Sinai West hospital, where she was pronounced dead.
Goodson's 1-year-old daughter, Rhylee, was found underneath her in good condition, sources said. He says family meant everything to her and she was very protective.
The MTA has pledged to make 50 more stations accessible by 2023, but this falls far short of complete accessibility.
Goodson's death remains under investigation and an autopsy will later determine her exact cause of death.
"While the cause of death is pending in this case, we can state that there is no significant trauma, and this fatality appears to be related to a pre-existing medical condition", Chief Medical Examiner Dr. Barbara Sampson said.
Rhylee is now in the custody of her father, in the Bronx.
The Metropolitan Transportation Authority (MTA), which also is investigating, called Ms Goodson's death "a heartbreaking tragedy".
Andy Byford, who was appointed the MTA's head of the subway system last year after running the Toronto Transit Commission, has set a goal of adding enough elevators to the system that after five years, no rider will be more than two stops away from an accessible station.
In a statement to WPIX, MTA officials expressed sadness over the incident, and highlighting its Fast Forward plan, which officials have said will address accessibility.
The 53rd St and 7th Ave station does not have an elevator.
Malaysia Goodman's mother, Tamika, started a GoFundMe campaign to raise money for her daughter's funeral. "NYC must do more for families and the disabled".
The incident has again raised the issue of accessibility on the city's subway.