OF THE PENNSYLVANIA RAILROAD COMPANY ITS PREDECESSORS AND SUCCESSORS AND ITS HISTORICAL CONTEXT: 1972 (PDF). Pennsylvania Railroad Technical & Historical
哥伦比亚铁路桥(英語:Columbia Railroad Bridge,也叫做“哥伦比亚桥”,"Columbia Bridge")是费城的一座混凝土拱桥,由CSX運輸运营的铁路线使用,跨过斯库尔基尔河,1920年建成。 "The Reconstruction of the Columbia Bridge
30th Street Station to Market East Station (PDF). The Pennsylvania Railroad Technical and Historical Society. 2007 [2022-05-09]. (原始内容 (PDF)存档于2011-09-19)