Sofia Globe writes Construction of the longest railway double tunnel in Balkans began on July 15, Bulgarian caretaker Transport Minister Georgi Todorov said. 498 million leva investment comes from European Union.

Elin Pelin Vakarel Railway Line and tunnel are built by Turkish consortium of Cengiz Construction-Duygu Engineering Partnership (DZZD Cen-Duy Demiryolu Elin Pelin İş Ortaklığı).

Cengiz & Duygu beat 9 companies from Türkiye (other Turkish companies), China, Spain, Italy, Greece, Portugal, Poland and Bulgaria in this tender bidding.  Bidding price was 255 million Euro.

For constructıon New Austrian Tunneling Method (NATM) will used. It will become longest railway tunnel of Bulgaria.

Railway length is 20 kilometer and tunnel length is 7,68 kilometer. It is double tube. The railway is part of Sofia Plovdiv railway line. 1 Billion euro allocated for it.

https://sofiaglobe.com/2021/07/15/bulgaria-construction-of-longest-railway-double-tunnel-in-balkans-begins/