Wisconsin Central Bridge Ruins, Somerset, WI (johnweeks.com) The Wisconsin Central bridge over the Saint Croix river was built in 1884 by the Union Bridge & Iron Works. The Wisconsin Central was pushing west, and this bridge was the last link to connect Milwaukee and Chicago to Saint Paul. The bridge features a number of very well crafted cut-stone piers. There were nine 160-foot deck truss spans, one 160-foot pin-connected though truss span, and 25 plate girder spans, each 30-feet long.