The pier in the middle makes me think two DPG spans.
I took a best guess when I posted it based off the pixelated squiggles on the track chart. Corrections welcome.
Found in a 1970 track chart:
Bridge #I-812
3-15' C. Br
Steel Br Deck 100'x28'
2-16' Sp C. Br
Doesn't specify one span, could've been 2-50' spans or a similar configuration?
Does not appear to be a single 100ft DPG as there is a pier in middle. Someone with a track chart could perhaps look up the appropriate span info.
A good mystery here. Based on the difference in elevation between top of pier and the top of rail would be somewhat inclined to give thought that it may have been a variant of truss spans as opposed to DPG. Or perhaps since track charts say DPG they were used as a replacement for washout. Didn’t post the pic but original bridge was a timber pile trestle our canoe drug across the timbers.