This photo (I took in 2006) is in the public domain and shows the bridge quite well, along with a pair of heavy Chinese QJ steam locomotives. Railroad bridges always seem to look better under steam.
I don't know any of the exact dates, nor what the original bridge was. I've been assured that there used to be a different bridge on these piers, the old people who have told me this can't remember what exact type, but it was not just a single deck girder.
If you know the history and year of the piers you should add it to the bridge description.
Looks like those piers are from a much older bridge.