A causeway across the middle of the Great Salt Lake divides the lake in half. It is part of the Lucin Cut-off, which is one hundred miles of railway built by the Southern Pacific Railroad to bypass the steep grades and curves on the portion of the transcontinental railway between Ogden and Lucin. The wooden trestle across the lake, finished in 1904, was an engineering wonder of its time. Over 23 miles of trestle was built in the water (much of it used just for the construction), using over 28,000 piles, each around 120 feet long. It was filled in, becoming a solid causeway, in 1959, effectively dividing the lake in two parts. The northern part has become saltier, while the southern part has become less salty. Its current owner, Union Pacific, cut a 150-foot long breech in the causeway in December 2016, hoping to address the problem. The 11.8-mile span of the causeway across the Great Salt Lake remains the longest railway viaduct in the country.