The BORFLEX Group wishes the Gotthard Tunnel a happy anniversary: 10 years at the heart of the Alps

Ten years after the opening of the Gotthard Base Tunnel, the BORFLEX elastomer liners continue to perform without requiring any maintenance

June 1, 2026 marks the tenth anniversary of the opening of the world’s longest railway tunnel. For the BORFLEX Group, the event provides an opportunity to reflect on a decade of continuous operation of its elastomeric liners deep within the Alps—and to position its technology for major projects in the future.

TABLE OF CONTENTS:

• A decade of proven service in the heart of the Alps
• BORFLEX slippers at the Gotthard Pass: landmarks
• The ballastless track market is gaining momentum
• Integrated engineering, from formulation to simulation
• Key Technical Specifications
• Projects across five continents
• Technological Innovation and Integrated R&D
• Available media resources

A decade of proven service in the heart of the Alps

Inaugurated on June 1, 2016, by the heads of state of Switzerland, Germany, France, and Italy, and opened for commercial service on December 11, 2016, the Gotthard Base Tunnel (57 km) is the flagship project of Switzerland’s New Rail Link through the Alps (NRLA) program. Ten years later, the infrastructure handles heavy traffic of up to 260 freight trains and 65 passenger trains per day, under some of the most demanding vibration and mechanical stress conditions in the world. At the heart of this infrastructure are 212,000 elastomeric pads developed and manufactured by the BORFLEX Group, which encase the double-block sleepers and ensure their isolation from the concrete slab. Installed along 57 km of ballastless track, these components simultaneously reduce vibrations transmitted to the bedrock, attenuate structure-borne noise, provide electrical insulation for the tie, and allow for the replacement of individual components without major infrastructure work.

“ Ten years of continuous operation without replacement is the most rigorous industrial validation test there is for a railway elastomer component. Complete mastery of the entire process—compound formulation, finite element simulation, mechanical qualification on an MTS Landmark test bench, and mass production—is our decisive competitive advantage.” — Thierry GERME, KAM Railway, BORFLEX Group

BORFLEX slippers at the Gotthard Pass: landmarks

• Quantity supplied: 212,000 slippers
• Length of track equipped: 57 km
• Delivery period: 2013–2014–2016
• Maximum operating depth: 2,300 m below the mountain range
• Traffic capacity since 2016: up to 325 trains per day (freight and passenger)

The ballastless track market is gaining momentum

The Swiss case study comes at a pivotal moment for the global ballastless track market. According to Verified Market Reports, the segment was valued at $3.2 billion in 2024 and is projected to reach $5.5 billion by 2033, representing a compound annual growth rate of 7.1%. Other firms (Dataintelo) project even higher market values, reaching $10.5 billion; however, all agree on the underlying structural dynamics: urbanization, modal shift, and growing noise control requirements in dense urban areas.

Tunnel applications are the fastest-growing segment. Major projects currently underway—including the Lyon-Turin line (Mont-Cenis, 115 km), the Brenner Tunnel (64 km, scheduled to open in 2032), and metro extensions in Asia and the Middle East—rely primarily on double-block sleeper solutions with elastomeric pads, for which BORFLEX is one of the leading European suppliers.

Integrated engineering, from formulation to simulation

Developed and refined since 1978, BORFLEX technology is based on an integrated system comprising an elastomeric insole, a microcellular rubber sole with calibrated static and dynamic properties, and, depending on the configuration, a connecting bar between the two blocks of the crosspiece.

Key technical specifications:

• Reduced transmission of vibrations to the ground and surrounding buildings
• Reduction of structure-borne noise generated by rail traffic
• Static and dynamic stiffness optimized using finite element analysis (FEA)
• Compatibility with LVT double-block sleepers, with or without a connecting bar, as well as with subway and tram tracks
• In-house developed elastomer compounds, including variants that incorporate recycled rubber (VALUE RUBBER program)
• Manufacturing by vulcanization (compression, transfer, injection) or injection molding of thermoplastics
• Integrated electrical insulation, protecting infrastructure from the spread of stray currents
• IRIS and ISO 9001 certifications; compliance with REACH, RoHS, and Euroclass standard NF EN 13501-1

Projects across five continents

Beyond the Gotthard Pass, BORFLEX track pads are used in some of the world’s most demanding railway projects:

Technological Innovation and Integrated R&D

The BORFLEX Group continuously invests in its research and development capabilities. The group has an in-house materials characterization laboratory, an MTS Landmark hydraulic test bench for mechanical qualification, and expertise in advanced finite element method (FEM) simulations for the design of elastomer parts. This data-driven approach ensures precise optimization of the static and dynamic stiffness of each component, in accordance with the regulatory requirements of each project.

Available media resources

Video presentation of the deployment at the Gotthard Base Tunnel

Technical exploded view of the shoe

Infrastructure Brochure

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