Bridge four-lane highway on the upper level and a pair of railway tracks at the lower level. Tower Bridge in London is different example of a double-decked bridge, with the central section consisting of a low level bascule span and a high level footbridge. A viaduct is made up of multiple bridges connected into one longer structure. The longest and some of the highest bridges are viaducts, such as the Lake Pontchartrain Causeway and Millau Viaduct. A three-way bridge has three separate spans which meet near the center of the bridge. The bridge appears as a "T" or "Y" when viewed
Tower Bridge (California) an agreement reached on March 8, 1934. Under the terms of the agreement, Sacramento Northern Railway relinquished its rights to the 1911 M Street Bridge in return for the rights to rail traffic over the new bridge until March 21, 1960, which was the original expiration date of its franchise to operate rail traffic over the 1911 bridge. Construction commenced on July 20, 1934. Road traffic was diverted to the I Street Bridge, and rail traffic was diverted to a temporary timber-and-steel "shoofly" bridge approximately of the existing M Street Bridge. Tower Bridge was initially designed with a wide roadway