I found a book in my local library that is, apparently, one of those paperback books that is self-published by a museum for sale in their gift shop. It's from the Milwaukee Public Museum, called Historic Wisconsin Buildings: Survey in Pioneer Architecture by Richard W.E. Perrin. (Second Edition, 1981, Original Pub date 1973.) Perrin has photos of three Wisconsin stone arch bridges, including the Shioc River Stone Bridge in Outagamie County between Shiocton and Shawano, and the Palm Tree Road Bridge over the Sheboygan River, near St. Cloud in Fond du Lac County.
Perrin says that when the Tiffany Stone Bridge was built, locomotives didn't weigh much more than 43 tons but since modern diesel locomotives weigh upward of 250 tons, the arches were reinforced with concrete rings.
He goes on to say that the Tiffany Stone Bridge was built in 1869, designed by a Chicago engineer named Van Mienen¹. The limestone from the area was not considered to be strong enough to hold locomotives, so the substructure stone was shipped in from Wapun and the superstructure stone came from Duck Creek in Brown County, near Green Bay.
It is a stunning structure and local residents are justifiably proud of it. It is considered to be the oldest stone arch bridge extant in the state of Wisconsin, predating the Goette Road Bridge by 8 years. A friend of mine, who is the director of the historic Yerkes Observatory in Williams Bay, put me on to this bridge a couple of years ago. A tip o' the hat to Jim for sending me on the hunt for this bridge.
¹ - Author's Note: Van Mienen was the chief engineer of the Chicago & Northwestern Railway Company, that had been formed by the merger of several railroad companies. Van Mienen's designs were inspired by classical arch bridges, this one, in particular, from a bridge in Campiègne, France. (The Chicago & Northwestern provided the link between Chicago and Omaha in the transcontinental railroad. The Union Pacific continued the transcontinental railroad west from Omaha. Today, the Union Pacific owns much of the old C&NW, including this bridge.)