of the arrival of the first train via the First transcontinental railroad to reach the shores of San Francisco Bay, thus achieving the first coast to coast transcontinental railroad in North America. The Croll Building, on the corner of Webster Street and Central Avenue, was the site of Croll's Gardens and Hotel, used as training quarters for some of the most popular fighters in boxing from 1883 to 1914. Jack Johnson and several other champions all stayed and trained here.] The need for expanded shipping facilities and increased flow of current through the estuary led to the dredging of a tidal canal through the marshland between Oakland and Alameda. Construction started in 1874, but it was not completed until 1902, resulting in Alameda becoming an island. Modern era In 1917, a private entertainment park called Neptune Beach was built in the area now known as Crab Cove, which became a major recreation destination in the 1920s and 1930s. Both the American snow cone and the popsicle were first sold at Neptune Beach. The Kewpie doll became the original prize for winning games of chance at the beach – another Neptune Beach innovation. The park closed down in 1939. The Alameda Works Shipyard was one of the largest and best-equipped shipyards in the country. Together with other industrial facilities, it became part of the defense industry buildup before and during World War II, which attracted many migrants from other parts of the United States for the high-paying jobs. In the 1950s, Alameda's industrial and shipbuilding industries thrived along the Alameda Estuary. In the early 21st century, the Port of Oakland, across the estuary, has become one of the largest ports on the West Coast. Its operators use shipping technologies originally experimented within Alameda. As of March 21, 2006, Alameda is a "Coast Guard City", one of seven then designated in the country. As of 2018, it is one of twenty-one within the country. In addition to the regular trains running to the Alameda Mole, Alameda was also served by local steam commuter lines of the Southern Pacific (initially, the Central Pacific). Alameda was the site of the Southern Pacific's West Alameda Shops, where all the electric trains were maintained and repaired. These were later adapted as the East Bay Electric Lines. The trains ran to both the Oakland Mole and the Alameda Mole. In the 1930s Pan American Airways established a