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
London Bridge – Greenwich Railway Viaduct London Bridge – Greenwich Railway Viaduct The London Bridge – Greenwich Railway Viaduct consists of a series of nineteen brick railway viaducts linked by road bridges between London Bridge railway station and Deptford Creek, which together make a single structure in length. The structure carries the former London and Greenwich Railway line and consists of 851 semi-circular arches and 27 skew arches or road bridges. It is the longest run of arches in Britain, It is also one of the oldest railway viaducts in the world, and the earliest example of an entirely elevated railway line. It was built between