Amsterdam Metro Reaches New Depths

Currently, public transportation--whether bus, tram, or metro--in Amsterdam, The Netherlands, carries approximately one million passengers each day. Ridership is expected to accelerate after 2012 when a north-south metro line opens. A major engineering challenge for Amsterdam is the country's first bored-tunnel metro line, featuring twin bored tunnels, both of which are 6.5m in diameter and 3.2 km in length. A busy city center, historic buildings, and a high water table are just some potential obstacles. Three different techniques are being employed to minimize the street level chaos and type of demolition that resulted from 1970s metro line construction. Demolition is limited by running the majority of the route under existing canals and streets; new tunneling advances make the bored tunnels technically feasible, despite a high water table and soft peat and clay layers; and city center station construction sites are covered. The author discusses facets of construction in various geographic locations, as well as safety and new trains.