The 4,000t, 112-long machine is now being assembled at the construction site in Babica. The TBM, named Karpatki, has a diameter of 15.2m – the largest ever used in Poland.

Crawler cranes with lifting capacities of 300-650t will be used to assemble the TBM.

Last year Acciona and its Polish subsidiary Mostostal Warszawa were awarded the €500m design and build contract for the 10.3km section of the S19 highway in south-east Poland, including a 2.2km dual tunnel, between the Rzeszów Poludnie junction and Babica. The two bores will be connected by 12 emergency passages.

With an alignment through hilly terrain and complex geology, the project is considered to be one of Poland’s most technologically advanced infrastructure undertakings.

“The scale of construction, technology, know-how and specialised TBM equipment is incomparable to most investments currently being designed and implemented in Poland,” said Jorge Calabuig Ferre, vice-president of Mostostal Warszawa.

There will be 32 alarm points, 28 rescue refuges and 28 hydrants along the length of the tunnel. It will be equipped with transverse ventilation.

The S19 expressway also includes six overpasses and two viaducts.