TRAVELLING BETWEEN Sweden and Denmark will be made even easier by Malmo's Citytunneln project, which has just gone out to tender.
It will provide a direct link, via the 0resund crossing, from the Swedish city's rail network to the Copenhagen metro across the strait.
Rising passenger train traffic to and from continental Europe has made expansion of the railway through Malmo necessary. The city's regional mass transit system will also benefit from the scheme.
Tenders for the SEK7. 7bn (£523M) project will be let as two large contracts and 20 smaller ones.
The largest contract, for the tunnels, is valued at £204M.
The second large contract, valued at about £68M, covers Malmo central railway station which will be replaced with a new station in a cut and cover tunnel with four tracks and two 320m long platforms.
A 6km twin tunnel will run 12m to 25m beneath the city. Of this 4. 5km will be bored and 1. 5km in cut and cover.
Closed face TBMs with 9m diameter boring heads will be used to construct the tunnels, which will be concrete lined. Twelve interconnecting shafts used for electrical and mechanical equipment will also serve as evacuation routes joining the two main tunnels.
Geology below Malmo is primarily limestone under a layer of boulder clay, with Copenhagen Limestone underlain by Bryozo Limestone. The Copenhagen Limestone is fractured and highly water bearing, whereas the Bryozo formation is relatively dense and impermeable. Most of the tunnelling will be carried out in the Bryozo Limestone.
'The challenge will be to find a TBM that bores through limestone in a problem free manner, ' says tunnel project director Laust Ladefoged. He expects the tunnelling rate to be 60-80m a week.
Two new stations will be added to the line.
Triangeln station will be in the middle of the city's commercial and cultural centre, 22m underground.
Hyllie station will be built at ground level in a developing area between Malmo and the Swedish coast.
Some 3M. m 3of material will be excavated during the project, 600,000m 3of it from beneath Malmo. Some of the excavated material will be used as noise barriers and backfill at Hyllie and some will be used as fill in Malmo's northern harbour.
By 2010, an estimated 40,000 passengers will use the Malmo Central and the Triangeln stations every day. The number of trains through the Citytunneln in 2010 is predicted to be between 350 and 450 a day.
The project is due to be operational by the first half of 2008.