City officials have been discussing the 125-foot West Main Street bridge, built in 1888 and listed on the National Register of Historic Places, for a quarter century – most intensely in the last half-dozen years. The bridge is so deteriorated that it has been closed even to foot traffic. The city engineer said last week that the historic bridge “is in a state of failure.” A temporary bridge has been installed alongside it for the many West Side pedestrians who need to cross Mill River to get downtown. Members of the Board of Representatives’ Operations Committee discussed the three projects last week. The double-span, wrought-iron lenticular truss bridge was built by a Connecticut company, Berlin Iron, that was known nationwide for the design. The Stamford bridge is one of only eight left in Connecticut, and one of the last historic structures in the downtown.