The woman, in her 30s or 40s, was killed at the 59th Street N/R station in Sunset Park around 8:15 a.m.
It was initially believed she was trying to retrieve her cell phone, but police say further investigation revealed the death to be a suicide.
No other injuries were reported, but a subway suspension made for a rough commute for many riders heading to work.
Train service resumed a short time later.
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