This bridge was designed to "fit in" with the other bridges... but also to look a little different. The intent was not to fool people into thinking this was a historic bridge.
Design includes 1930s style art deco details and an "Eagle's Nest" overlook reminiscent of the earlier, historic highway bridges.
I am not certain, but it looks like the same culvert under the rail crossing as in the photo below. If it is, then it is by far the oldest surviving feature in the area!