February 21 (SeeNews) - Serbian state-owned company Infrastruktura Zeleznice Srbije said it signed an agreement with a consortium of companies led by China Railway 21st Bureau Group - a subsidiary of construction company China Railway Construction Corporation Limited (CRCC) - on the construction of a railway tunnel worth 40.8 million euro ($46.4 million) between the country's southern towns of Stalac and Djunis.