After three months of invisibility, the tunnel boring machine, named Molly, appeared once again, emerging at exactly the right place in Ceintuurbaan station, one of the stations of the North/South Line in Amsterdam.
The maximum margin was five inches, but in reality, Molly arrived just five millimeters from the exact location, NRC reported last weekend.
Construction delays (the underground railway will not be operational in 2013 as planned, but rather in 2017), cost increases (from 1.4 billion to 3.1 billion), leaks in slurry walls, and collapsing houses: constructing a line running from north to south has seemingly swallowed the city of Amsterdam. It is therefore a relief that Molly did her work properly and on schedule. How is it possible that this part of the North/South Line went so perfectly smoothly?
Lecturer John Baggen (Faculty of Technology, Policy and Management and Faculty of Civil Engineering and Geosciences) attributes it to experience. “Tunnel boring machines have been used during the last decade in the Netherlands, for example to construct tunnels in the Betuweroute and the High-Speed Line South,” he explains. “But it’s the first time this method is being used in Amsterdam. They didn’t dare use it during the 1970s, when the East Line was constructed”
The East Line was the first underground railway in Amsterdam. It was mainly constructed above the ground, by building big concrete caissons that then had to be sunk. Consequently, a large part of the Nieuwmarktbuurt had to be demolished, which led to protests and even riots in 1975. The city of Amsterdam therefore decided that after completion of the East Line, no new lines would be built, despite the fact that plans drafted in 1968 envisioned connections between all districts in and around the city, with even a North/South Line and two East/West Lines.
“The design of the North/South Line therefore became more complicated than in the 1970s,” Baggen says. “You might wonder if that’s useful. They took the political decision that no building could be demolished. Therefore, in Ceintuurbaan station, the two tunnels and platforms are constructed above one other, which makes the construction extremely deep at this point [32 metres, ed.]. If you would have removed just a few blocks of houses at one street side, the station would have been a lot cheaper and less complex. Moreover, the houses are a dime a dozen in that area, and in the end two buildings were demolished anyway.”
Digging the tunnels has not caused any delays or overruns until now, according to Michael Jonker, a spokesman for the North/South Line. This is striking because the North/South Line has already doubled in cost. Baggen: “The East Line had also more than doubled in cost, from 400 million to approximately 1 billion guilders. This is because politicians are always tempted to reduce the costs of large projects. Otherwise, they would never be started”.
So when the North/South Line is finally completed in 2017, should the original network plan drafted in 1968 still be carried out? Baggen partly thinks so. “Since the East Line opened in 1977, it has been used a lot,” he says. “The North/South line is even more centrally located, so it will become a success, too. Perhaps the next project should be the construction of a West Line."
Pak m’n jas, m’n schoenenVerder niks van waardVoel me in m’n blootje lopenMet alleen die ov-chipkaart
Veeg langs een paalWaar ergens verscholenIets me leest, me bestraaltMe vervlecht in parabolen
De conducteur doet haar rondeZe scant me en kniktBevindt me ook zonderBestemming geschikt
‘Waarheen?’ was geen vraagVoor het licht in de bomenDat achteloos reisdeOm waar ook te komen
Blijf als een veer in de luchtMijn reisdoel rekkenNaar onbekend terrein en terugZolang … ik niet vergeet me uit te checken
Bauke Steenhuisen doceert aan de faculteit Techniek, Bestuur en Management en is winnaar van deDelftse Poetry Slam 2010.