A 1930 steel stringer bridge over the Mississippi River in Morrison County, Minnesota, also serves this purpose. The railroad and the highway share the same bridge deck.
R.R. St. in Rome,N.Y. has done this since 1900, and continues to handle both cars & trains today.
This bridge also carried cars and trains up till 1979. And still has a grate decking on each side of the truss. (might be made into a pedestrian bridge soon.
My guess is that there were more than two in the world that accommodated rail and road traffic on the same surface. One that comes to mind is the James St. Swing Bridge in Thunder Bay, Ontario. See attached photo.
Photos of the bridge in 2001 when it still had the part that cars could drive across.
"Until it's closure to automobile traffic in 2000, the Naheola Bridge was one of only two bridges in the world that accomodated rail and auto traffic on the same traveling surface. Traffic lights were mounted at each end of the bridge to signal the auto traffic to stop or proceed. The lights were controlled by the drawbridge operator, who was stationed in the bridge house near the middle of the bridge. This was necessary because the bridge is only wide enough for one-way traffic, and motorists could not see from one end of it to the other because the half-mile long structure had a blind curve at one end. The lights were also necessary to warn motorists of the presence of a train or the possibility of the drawbridge being in a raised position to allow barge traffic underneath."