Safety issues were top priority in the design of the Copenhagen metro system.
Main contractor, Copenhagen Metro Construction Group (COMET) specified a maximum distance of 300m to the nearest emergency exit along the line. In the underground tunnels, this meant excavating vertical escape and ventilation shafts between the nine underground stations. These circular shafts are typically 20m to 30m deep, with a diameter of around 8m, with passages leading from the bottom of the shafts into the tunnels.
In each of the nine escape shafts there are large diameter ventilation ducts, a flight of stairs, and an emergency lift from Swedish hoist manufacturer Alimak, which added some special features to its 1,200kg capacity rack and pinion lift model Alimak SE-12 to suit the application.
The Alimak lifts have been equipped to take two stretchers in the car, allowing casualties to be moved to ground level in the event of an accident in the tunnels.
All lift cables are flame retardant to eliminate the risk of gas from burning cables in case of a fire. And a rear window in the car allows rescuers to check their bearings when travelling up and down the shaft.
Car size is 1.17m wide by 2.35m deep and the travel speed is 0.8m/sec.
In just a few years time 21km of new metro lines will be added to Copenhagen's existing commuter network of buses and heavy trains.
Fully automatic, driverless trains will then link the eastern and western areas of the Danish capital, including an extension to the south and the new town within a town development centre of Ïrestad.
The first 11km of the metro will open in the autumn of 2002 with another 6km ready in 2003.
The third and final phase includes an extension to Copenhagen International Airport, scheduled to open in 2005.