The woman, Pratiksha Shinde (26), was a constable attached to the Local Arms Unit of the Mumbai police and originally hailed from Solapur, he said.
Her body was found on the tracks between Sion and Kurla stations on the Central Railway line at around 1.20 pm, the official said.
Prima-facie, it appears Shinde was knocked down by an express train while crossing the tracks, he said.
However, police are probing her death from all angles and not ruling out suicide, the official said.