Gov. Tom Corbett has kicked off a re-election tour that's taking him across Pennsylvania from Pittsburgh to Philadelphia over the next several days. But as he crisscrosses the state highlighting the growth of natural gas drilling, he's relying on a more traditional fuel.

Campaign staffers say Corbett's campaign bus does not run on compressed natural gas, or CNG; it runs on diesel. 

The campaign simply decided to use the same bus company it chartered in 2008, said Billy Pittman, the governor's press secretary.

But at a visit to a Luzerne County pipeline company that has benefited from Pennsylvania's natural gas rush, Corbett's campaign manager Mike Barley explained a CNG-powered bus would have been too expensive. Plus, there aren't enough places to fill up.

"I'd love to get it on CNG," said Barley. "We'll look into it. It's a matter of availability to be honest with you."

Despite the glut of natural gas being produced, using it as fuel for trucks and buses is only slowly catching on with municipalities, some utilities and energy companies. The Department of Transportation and the Department of Environmental Protection say the agencies do not keep track of how many private stations exist in the state.

There are currently 27 public CNG-fueling stations in Pennsylvania with more in the planning stages. Apparently, there were not enough to get the governor and his campaign team across the commonwealth.

"They're not as plentiful as they will be eventually, hopefully," Barley said.