Please note that the content of this book mainly consists of articles available from Wikipedia or other free online sources. The Alfred H. Smith Memorial Bridge is a railroad bridge that spans the Hudson River at Castleton-on-Hudson and Selkirk, New York, in the United States. The bridge is owned by CSX Transportation and was originally built for the New York Central Railroad, which later merged with Penn Central and then transitioned to Conrail before being acquired by CSX. The bridge is part of CSX's Castleton Subdivision. It is named in honor of Alfred Holland Smith, the president of the New York Central Railroad, who approved the construction of this bridge as part of a larger project known as the Castleton Cut-Off.