It happened in Mount Airy and the driver was taken to the hospital.
It turns out that more and more SEPTA drivers are being attacked and the Transit Agency is taking steps to protect them.
The face of Gary, a SEPTA driver, is still scarred from an attack two weeks ago, when he says a teen passenger lashed out.
"He punches me in the face and runs off the bus," Gary told Action News.
Gary says the force of the punch broke his teeth and bloodied his nose and, worse, he never saw it coming.
"It was shocking and it was scary because I was defenseless," he said.
But as seemingly random as Gary's story may sound, SEPTA says it is not rare.
They gave us exclusive video (seen above) of what, they say, are other attacks on drivers.
According to SEPTA executives, there were 18 reported assaults on drivers in all of 2010. So far this year, they say that number is 27.
"So we're on track to have 43, which would double, easily double, the number, so we'd be up over 100 percent from 2010," SEPTA's Chief Surface Transportation Offcier Michael R. Liberi said.
The attacks don't follow a pattern. They are not centered in one section of the city, or committed by any one demographic. But SEPTA says the victims are all drivers, simply trying to do their job, beaten or spit on by passengers for a whole host of reasons.
"They see an easy victim in a bus operator or a trolley operator," TWU Local 234 President John Johnson Jr. said.
Johnson is head of the SEPTA drivers' union and he, too, says he was the victim of an attack a just a few years ago.
"I felt the gun in the back of my head and I was like 'am I going to die today?'" Johnson said.
The prevalence of attacks has led SEPTA to begin installing cameras on board its buses and trolleys. Of 1,200 buses in the fleet, 500 are now equipped with several cameras each, with more and more being installed each day. The idea is to make potential criminals think twice.
"I would like to say that the numbers reflect that, unfortunately, they don't," Liberi said.
So now SEPTA officials are taking the next step, urging Pennsylvania state lawmakers to pass a bill adding transit employees to a list of protected public workers. If it's passes, those who harm them would face a minimum 5 years behind bars. That, they hope, will do what some cameras have so far not been able.
Until then, SEPTA has this plea - that to attack a driver is to put everyone else in danger.
"If an operator gets assaulted while they're operating a bus that becomes a loaded bullet," Johnson said.
Gary says he spotted his alleged attacker four days later. The boy, 17, was caught and arrested.
Police hope that if the cameras don't serve as a deterrent, they can at least help capture the suspects.