A 74-year-old man was shoved onto the subway tracks in an unprovoked attack on the Upper East Side early Tuesday, cops said.

The victim was standing on the downtown No. 6 train platform at the 68th Street-Hunter College station around 12:20 a.m. when a man suddenly shoved him onto the roadbed without saying a word, police said.

An on-duty MTA employee helped the straphanger back up onto the platform, cops said.

The elderly man, who suffered cuts on his fingers and complained of pain, was taken to Weill Cornell Medical Center, where he was listed in stable condition.

His attacker bolted from the station and escaped onto the street, cops said.

The two men did not interact at all prior to the random push, police said.

In an unrelated attack about a half-hour later, a 19-year-old man repeatedly slashed his 24-year-old girlfriend during a fight on board a Manhattan-bound No. 3 train at Pennsylvania Avenue in East New York, cops said.

The woman was slashed in the forehead, stomach and hand during the heated clash, police said.

She was taken to Brookdale University Hospital and Medical Center, where she was listed in stable condition.

Her boyfriend was arrested. Charges against him were pending, cops said.