Confusion and Sorrow for Trainer of Filly Larry Jones has watched the replay dozens of times. He has examined photographs of Eight Belles, and he still cannot fathom how the filly he trained was at one moment crossing the finish line in second place in the 134th running of the Kentucky Derby, and then in the next, she was gone. Jones was proud of Eight Belles as she stormed down the stretch, chasing the winner, Big Brown, a powerful colt. He is now heartbroken after she shattered her front ankles as she galloped out around the far turn and had to be euthanized on the racetrack. Mostly, however, he is mystified. “We have some photographers that we really got to know last year,” said Jones, who finished second here last year with Hard Spun. “They were on the first turn taking pictures as everybody was galloping out. “We’ve got a lot of great pictures, they say, of her, and she’s got her ears up and was not in any kind of distress galloping out around the turn. I don’t know what happened and when. Just all of the sudden, it just went.” Two years ago, Barbaro’s breakdown in the Preakness and his death later helped usher in an era of synthetic racing surfaces. The composition of these racetracks was designed to provide more cushion. The surface was installed at Keeneland in Lexington, Ky.; Arlington Park in Chicago; and at racetracks in California. But Churchill Downs Inc., which owns Arlington Park, has not embraced the move to a synthetic surface here at its flagship racetrack and home of America’s most famous horse race. “We like the racetrack we have right now,” said John Asher, a spokesman for Churchill Downs. “We’re studying the synthetic surfaces, but we want to see data for four or five years because the technology is evolving all the time. We want to know exactly what we’re getting.” Early results from studies of the safety of synthetic tracks versus dirt ones are promising but inconclusive. Dr. Mary Scollay, a veterinarian at Calder Race Course, organized an equine injury reporting system for more than 30 tracks and has found that fatality rates have been lower on synthetic surfaces: 1.47 fatalities per 1,000 starts for synthetic surfaces against 2.03 per 1,000 for dirt tracks....