The "pre-oxidizing" mentioned here is likely just referring to weathering steel. While it may be odd to see it on a RR bridge, it is used frequently in highway construction.
Not anymore. Like what they're doing all over the country, they're starting to re-route vehicular routes off of dams and making entirely new bridges of there own. You can't travel over this anymore. It has now been converted into a pedestrian walkway. But, they did build a UCEB on the river side for vehicular traffic. And, next to that, they built a 1 span Warren through truss railroad bridge. They're fairly new, they were finished in December I think.
There's a cool thing that they did with the railroad bridge that I've never seen before. They built the span on the ground, and pre-rusted it! They said by pre-oxidizing it that it'll save the state millions by not having to paint it. Huh. Anyways, someone go ahead and add these new bridges into the directory. I'm sure a lot of people from around the area would appreciate it. Thanks.
Diagram of the entire lay-out of both bridges
Keep in mind everything is already completed. I drove over the new bridge about a month ago.