The first of three underwater tunnel sections designed for Stockholm subway was manufactured in BLRT Grupp subsidiary BLRT Marketex. The structure will be installed in lake on piles 22 meters underwater.

Main customer is JVS (E. Pihl & Son A.S, Ed. Züblin AG). The item is unique: it weighs totally 2500 tons and has dimensions 300 x 20 x 9.5 m. The first section weighs 900 tons and is as large as 107 x 20 x 9.5 m. 90 employees were involved in the production, which took 5 months.

It is unique due to the fact that all welding seams were done under B class using 100 % ultrasonic test; welding seams are mostly done with welding tractor. Tolerance on dimensions is extremely strict ( ± 25 mm per 100 m)

The project suggests highly professional level of Estonian manufacturers.