The RediMix Rock Train heads over the San Pedro, Los Angeles & Salt Lake's Santa Ana River Viaduct. At the time that it was built, this bridge was the longest concrete arch bridge in the world, including ten arches each of 86 feet clear span, for a total length of 1,060 feet and a height of 60 feet. There are 25,000 tons of concrete poured into this engineering masterpiece. Today, it is accesible by taking a short hike in Martha McLean-Anza Narrows Park and you can watch hawks float in the stagnent air above while you wait for a train.