WHISTLER, B.C. - The design firm commissioned to build the Whistler Sliding Centre vowed to create the "most challenging" course ever made. It now promises to be the last of its kind. The International Olympic Committee is investigating how the course, originally designed for speeds of 137 km/h, allowed athletes to set world records of more than 153 km/h. Those speeds had athletes and officials questioning course safety leading up to the Games and yesterday's death of Georgian luger Nodar Kumaritashvili. "The track is too fast," Joseph Fendt, president of the World Luge Federation, told London's Daily Telegraph. "We had...