Pennsylvania Railroad Technical and Historical Society Railroad Museum of Pennsylvania Strasburg, Pennsylvania PRR Chronology — in depth PRR Corporate History PennsyRR.com — comprehensive PRR facts and history site, comprising multiple individual websites. prr.railfan.net — contains a lot of PRR information, including diagrams of passenger and freight cars as well as locomotives The New York tunnel extension of the Pennsylvania Railroad Transactions of the American Society of Civil Engineers, vol. LXVIII, Sept. 1910, by B.F. Cresson, Jr, from Project Gutenberg Orr, John W. , Penn State Press, 2001 ISBN 0-271-02056-3 Pennsylvania Railroad GG-1 p. 1 of 2: Stan's Railpix 1/16/1904;Sectional view Of Pennsylvania Railroad Tunnel Now Under Construction Beneath the Hudson River William G. Thomas "The Countryside Transformed:The Eastern Shore of Virginia, the Pennsylvania Railroad, and the Creation of a Modern Landscape July 31, 2007.