Washington, DC – A federal judge says the National Park Service was wrong to set aside the Clinton Administration plan to ban snowmobiles from Yellowstone and Grand Teton national parks. That decision late Tuesday comes just one day before the service had planned to open a winter season under rules that allowed snowmobiling to continue. US District Judge Emmet Sullivan in Washington, DC says the Bush administration has to revive the plan it scrapped. That plan phased the machines out in favor of mass-transit snow coaches, which would reduce pollution in the parks. The Bush administration came up with a plan to allow limited snowmobiling to continue. That plan required snowmobiles to have quieter and less-polluting engines. Sullivan's ruling does not entirely close the parks to snowmobiling. Instead, he ordered the Park Service to follow the older rules, which will eventually allow only snow coaches.