It happened on June 22 at 9:20 a.m.
Police say a 59-year-old man was walking from the PATCO station on the 1600 block of Locust Street when he was approached from behind by an unknown male.
The victim was grabbed by the throat and threatened with a box cutter.
Click here to watch the surveillance video
He tried to fight off the suspect, who then fled towards the PATCO platform.
There were no injuries reported.
Police describe the suspect as a black male, 40 to 50-years-old, 5'11" tall and 220lbs. with a heavy build and a surgical scar on his chest. He was wearing a black shirt, and green shorts, sandals, white socks, and was armed with a silver box cutter.
Anyone with information is asked to call police at 215.686.TIPS (8477) or text a tip to PPD TIP or 773847.