Take a look at what these mechanical engineering students from the University of Maine say is the only natural gas-powered snowmobile in the US. Why make all these changes to what used to be a stock Arctic Cat XF1100? To compete in the Society of Automotive Engineers Clean Snowmobile Challenge, which was founded to create machines capable of running in Yellowstone Natural Park where rules about noise and emissions keep gas snowmobiles out. Changing the fuel source from gasoline to natural gas not only meant swapping out the gas tank, but also the injectors inside the motor. As you can see in the video after the break, last year's team got the beast running, but this year students are working on improving the handling and tuning.