Major construction began Monday on the second phase of the light rail Expo Line from Culver City to Santa Monica with the drilling of piling holes for a new bridge over Olympic Boulevard at Centinela Avenue. When operational in 2016, the $2.4 billion, 15.2-mile Expo line will run between Santa Monica and downtown Los Angeles. Construction of the first phase, connecting Culver City to downtown Los Angeles, began in 2006,