Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Alfred H. Smith Memorial Bridge is a railroad bridge spanning 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 was subsequently merged into the Penn Central and then Conrail before being acquired by CSX. The bridge forms part of the Castleton Subdivision of CSX. The bridge is named in honor of Alfred Holland Smith, the president of the New York Central Railroad who authorized the construction of this bridge as part of an extensive project known as the Castleton Cut-Off.