Engineers and up to 2,000 workers in London have been stitching together and modernizing sections of three 19th-century urban railroads—two defunct and one live—to close a gap of under 3 km in the northeast corner of the city’s emerging orbital route. Slide Show Photo: Peter Reina / ENR A refurbished arch viaduct. Related Links: New Urban Rail Link: Threading an Historic Cityscape Over $1 billion is the expected end cost for the three-year project extending and improving this short stretch of Victorian-era infrastructure in the crowded metropolis. “It is a very complex project because here you are dealing with old
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.