By KEVIN VAUGHAN 9NEWS As the red gondola car suddenly bucked and shook on that morning 50 years ago, Greg Dietrich craned his neck, looked up, and realized the steel cable his life depended on had frayed and unraveled. It was just after 9:15 a.m. on March 26, 1976, at Vail ski resort, and the 19-year-old knew something was desperately wrong – part of the cable looked like a Slinky, and a strand of wire dangled from the line. Despite the shocking image, he could not have fathomed the kind of catastrophic mechanical failure that was underway on Gondola II, known as the Lionshead. Within minutes, two of the six-person cars would plunge 12 stories to the mountainside, killing three people on impact and injuring nine others, some grievously. Two days later, the death toll would grow in what remains one of the deadliest ski lift accidents in U.S. history. Gondola II climbed from Vail’s base at Lionshead up to a terminal at Eagle’s Nest, a distance of 1.8 miles and 2,200 vertical feet.…