Yes, it most certainly did - about the center 1/4 of it. From a ‘‘Wikimapia’’ article on it, at - http://wikimapia.org/1557066/Shocks-Mill-Bridge - also known as the ‘‘Shocks Bridge’’:
“The bridge was closed during the flooding caused by Hurricane Agnes in late June 1972. After the flooding had begun to abate, subsidence was noticed at the center of the bridge on June 27, 1972. On July 2, 1972, the six center spans collapsed into the river. The collapse of the bridge crippled the Penn Central Railroad, removing 75% of its capacity. With Federal aid, the bridge was rebuilt with nine concrete piers supporting steel girders replacing the destroyed center section.”
See pages 20 and 21 of 24 of the ‘PDF’ format version of the Penn Central Post employee magazine for August-September 1972, at [CAUTIONARY NOTE