XXL TBM Crosses Under the Panama Canal
Since September 2024, a Herrenknecht tunnel boring machine (TBM) has been excavating a metro tunnel under the Panama Canal. On February 2, 2026, the construction consortium HPH reached an important milestone with the giant TBM – diameter 13.5 meters – after passing under the Panama Canal: the breakthrough to the future Balboa metro station. From here, the last 1.5 kilometers remain to be completed before final breakthrough.
TBM breakthrough to the future Balboa station east of the Panama Canal on February 2, 2026
Credit/Quelle: Herrenknecht AG
On the occasion of the successful breakthrough Panama's President José Ral Mulino praised the outstanding performance of the tunnel construction team: “I congratulate all of you who made this challenging expedition under the canal possible.” The approximately 4.5-kilometer tunnel is the key structure of the new Metro Line 3, which will connect the western suburbs and downtown Panama City. Until now, 150 000 people commute across a bridge to and from work every morning and evening. The 25-kilometer journey currently takes up to several hours in constant traffic jams. César Pinzón, Director of Metro Panama, referred to this during the ceremony at Balboa station: “For thousands of residents, this first section is a concrete sign that the promised future is approaching, with fast and safe mobility.”
Over 60 Meters Below Sea Level
The construction of Metro Line 3 is a premiere: for the first time, a tunnel boring machine is crossing under the Panama Canal, one of the world's most heavily used and therefore most important waterways. The specifications are correspondingly strict, stipulating that the tunnel construction must not compromise the operational safety of the Panama Canal at any time. In view of the complex geology with high groundwater pressure over 60 meters below sea level, the contracted Consortium HPH with the companies Hyundai Engineering & Construction, Posco Engineering & Construction and Hyundai Engineering opted for a Herrenknecht machine of the Mixshield type. In order to be able to run the metro through the tunnel on two tracks, a correspondingly large tunnel diameter was planned – with a TBM diameter of 13.5 meters. This makes it the largest machine of its kind in Latin America.
Since tunnelling began in September 2024 on the western shore of the Panama Canal, the teams have been steering the large machine safely and with ever-increasing performance toward its destination. They mastered the critical crossing under the Panama Canal without any problematic incidents. In October 2025, they achieved their peak performance to date of 150 segment rings or 300 meters per month. After breaking through to the future Balboa station east of the Panama Canal on February 2, Herrenknecht specialists are now helping the Consortium HPH team get the XXL TBM ready for the last stage of about 1.5 kilometers to the final breakthrough.
