 The lift bridge is the last of several previous crossings over the waterway . A wooden swing bridge was built in 1875 . A newer , iron swing bridge was built in 1897 ; this structure was partially destroyed in 1905 when it was struck by a ship . This second crossing was rebuilt in 1906 and remained in service until the lift bridge was opened in December 1959 . The current bridge was last used for railroad traffic in the summer of 1982 , after the Soo Line rail lines north of Houghton were abandoned starting in 1976 . The middle section is left in an intermediate position for the warmer nine months of the year so that vehicle traffic can use the lower deck of the lift span and pleasure craft can pass under the bridge . In the winter , the lift span is lowered so snowmobiles and skiers can use the lower deck while cars and trucks use the upper deck . 
