Part of the reason tracking down information on this span is a bit of a challenge is that there is a second set of piers that share these construction details, which share the same adjacency to the current Amtrak Susquehanna River Bridge - One set over the River followed by a pair over the Chesapeake just downstream, I believe the like and also empty set over the bay originally carried the PW&B 1880 span pictured in your reply.
I spent eight months in the area on a bridge restoration but ten miles away (it was seeing the empty piers which began this in depth look) and got to know a number of area historians, and was told of the re-purposing then.
All that said, and I could have been told wrong. I have found contradictions aplenty. In part the hard to churn up aspect of this story is about confused information over two different nearby bridges. In part it is hard to believe the the PW&B would replace a two million dollar investment in less the fifteen years, could they have reached payback in that short span of time?
Luke -
I hope you don't mind if I edit the add. I have for some while been working to amass enough information to add it to this database.
I'm tossing a heads up because my edit would not just add information such as number of spans (13 @ '250 plus a Drawspan of '176 for a total of '3500) and the involvement of Parker & Powers, but would need to discuss the fact that this bridge had a service life far in excess of a single decade, and was not lost until the 30's - It was even re-purposed (after it was replaced by the adjacent and still in service'06 Iron Howe) in 1910 for vehicular use with ramp access' and floor beams and railings added in '27 for an additional travel lane, so it served as both a Through & Deck truss - One way travel in opposing directions.
Some background here > http://bridgewright.wordpress.com/2011/09/01/lost-to-evermor...
Additional information added from PRR Triumph VI by Roberts & Messer (2003)