Strabag SE has been assigned to begin one of Austrias biggest infrastructure projects.Carinthian Freedom Party (FPK) Governor Gerhard Dörfler announced today (Fri) that the Vienna-based market leader was contracted to build both sections of the Koralm tunnel.The railway tunnel will connect the Carinthian capital of Klagenfurt and Graz in Styria from 2022. Strabag said it planned to finish its part of the construction in 2018. Around 1.2 billion Euros have already been invested in the construction of the tunnel.Strabag is Austrias biggest building firm and one of the biggest players in Central and Eastern Europe (CEE). The company is also involved in the construction of the St. Gotthard Tunnel in Switzerland. The 57-kilometre tunnel will be the longest tunnel in the world when it opens for railway service in seven years.The 32.5-kilometre Koralm tunnel is one of the most disputed traffic projects in Austria. Social Democratic (SPÖ) Infrastructure Minister Doris Bures said the construction will cost at least 5.2 billion Euros, but some business experts warned costs may amount to twice as much.Karl Aiginger, head of Viennese think tank Institute for Economic Research (WIFO) has expressed doubts whether building the tunnel is a sensible investment considering its high costs and the economically bad state the Federal Railways (ÖBB) are in.Other analysts doubted there would be sufficient demand to justify spending billions on the Koralm tunnel and other tunnel projects in Styria and Tyrol. ÖBB, which has debts of 12 billion Euros, will be forced to use a credit to finance the construction of the Koralm tunnel.Bures previously claimed the construction of the Koralm tunnel will be finished in 2020 before putting back the deadline by two years following last weekends 2011-2013 state budget talks with SPÖ colleagues and representatives of the Peoples Party (ÖVP).ÖBB works council chief Wilhelm Haberzettl recently suggested postponing the construction of the Koralm tunnel and focusing on improving the ÖBBs overall service and connections instead. The SPÖ MP also called to cancel Tyrols Brenner base tunnel project.The ÖBBs debts are expected to soar to 20 billion Euros during the next four years. The state-owned firm headed by Christian Kern suffered losses of 46 million Euros during the first six months of this year. ÖBB currently spends around 43 per cent of its overall expenses on staff incomes. Kern said he wanted to get the company back in the black by 2013.