Sean P. Abt, 24, was arrested Tuesday evening and charged with assault in connection to the random Dec. 27 attack on the septaugenarian at Stryker Court and West 1 Street in Gravesend, police said. 

The victim was riding a Brooklyn-bound No. 4 train approaching the 42nd Street Midtown hub around 2:10 p.m. when she got into a dispute with a woman who appeared to be decades her junior, police said.