The suspect asked, "What are you looking at?" then hit a man in the Crown Heights station, police said.
Two men riding the northbound train were attacked by a group near 96th Street, police said.
The woman was pronounced dead at the scene, officials said.
The 2, 3, 4, 5, 6, 7, A, C, D, E, F, G and J lines are slated for service changes this weekend.
The suspect called the victim "stupid" and socked him, the NYPD said.
A man was hit by an F train in the Fourth Avenue station Monday morning, officials said.
The 1, 2, 3, 4, 5, 6, 7, A, D, E, F, G, N and R lines are all slated to undergo service disruptions.
A "rail condition" suspended N and Q trains between the boroughs and re-directed the R, the MTA said.
'Nightmare: New York' includes a ride on a graffiti-covered subway car.
A thief reached into the pocket of a 31-year-old man who had fallen asleep on the train, police said.
The 2, 3, 4, 5, 6, 7, A, E, F, G, J, N, Q and S trains will all be disrupted this weekend.
Alajuwon Aleem, 22, bit a man who tried to stop him from stealing a friend's purse, police said.
James Barnes also punched and kicked the woman in the DeKalb Avenue subway station, police said.
Uptown riders will need to find alternatives above 96th Street.
P.S. 85 in Astoria is so noisy that students have to hold up hand signals when they can't hear.
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