Taiwan boasts an extensive network of dedicated bikeways, many of which are transformed from former railway lines, and the Sandiaoling Eco-Friendly Tunnel is one of them. Nestled in the lush mountains of northern Taiwan, the Sandiaoling Eco-Friendly Tunnel is a fascinating destination for nature lovers, railway enthusiasts, and eco-tourists alike.
The Sandiaoling Eco-Friendly Tunnel is a unique structure consisting of two historic tunnels, each offering a distinct experience. The first, the 1.8km-long old Sandiaoling Tunnel (三貂嶺隧道), serves as a bat sanctuary where visitors can see over 50 unique Taiwan leaf-nosed bats (臺灣葉鼻蝠). The second, the 110-metre-long Sanguazi Tunnel (三爪子隧道), is home to the breathtaking “Mirror View” at the entrance to the Keelung River.
Watch the following video of Sandiaoling Eco-Friendly Tunnel in Northern Taiwan for more interesting images.
In particular, the shallow water covering the ground creates a striking reflection of the surrounding landscape, making it a popular spot for photography. As these tunnels seamlessly blend history, ecology and architectural ingenuity, it won the first prize at the Grand Prix AFEX 2023 Awards, a prestigious French architectural competition.
History of the Sandiaoling Eco-Friendly Tunnel
The old Sandiaoling Tunnel was built by the Japanese government in 1922 for coal transportation. After the Nationalist government moved to Taiwan, the tunnel was converted into a railway tunnel for Taiwan Railway’s Yilan line. However, the railway was diverted to a new track due to its narrow width and single-track capacity. In 1985, with the completion of the new Sandiaoling Tunnel, the old tunnel was officially decommissioned.
In recent years, local authorities and environmental organizations have recognized the old Sandiaoling Tunnel’s potential as a tourist attraction that promotes sustainability while preserving the area’s natural beauty. In 2015, the tunnel was renovated and converted into an eco-friendly pathway, allowing visitors to explore the scenic landscape and learn about the region’s history in an environmentally responsible way.
At the Keelung River entrance of the Sandiaoling Eco-Friendly Tunnel, a historic stone inscription bearing the characters “至誠動天地” (Sincerity Moves Heaven and Earth) stands as a testament to the past, inscribed by the 7th Governor-General Akashi Motojiro during Japanese rule. Likewise, at the entrance of the old Sandiaoling Tunnel, another preserved plaque bears the inscription “萬方輻湊” (Convergence from All Directions), inscribed by the 8th Taiwan Governor-General Den Kenjo, symbolizing the tunnel’s historical significance as a hub of transportation and connection.
These inscriptions, along with the tunnel’s original masonry and brick arches, have been remarkably well-preserved over time. Together, they serve as a bridge between past and present, highlighting the tunnel’s architectural integrity while enriching its cultural and historical value.
The design of the Sandiaoling Eco-Friendly Tunnel
The design of the Sandiaoling Eco-Friendly Tunnel embraces a unified and sustainable approach by exclusively using steel for all structural elements. To blend with the natural environment, the steel is first allowed to rust, creating a weathered appearance, before being coated with anti-rust paint to prevent further corrosion. Every facility along the route, including pathways, seating, handrails, bike racks, and interpretive signs, is crafted from steel, ensuring a cohesive aesthetic.
Additionally, great care has been taken to preserve all existing trees along the route, allowing the tunnel to integrate seamlessly with its surrounding ecosystem while maintaining a balance between human accessibility and environmental conservation.
Features of the Sandiaoling Eco-Friendly Tunnel
The Sandiaoling Eco-Friendly Tunnel is celebrated as Taiwan’s first “rebar bikeway.” This innovative design integrates steel reinforcing bars (rebar) into the tunnel’s structure, providing a distinctive and sustainable bikeway.
During its 37 years of abandonment from 1985 to 2022, the Sandiaoling Tunnel remained undisturbed by human activity, allowing its ecosystem to flourish. Bats took shelter within the tunnel, while the flooded floor became a habitat for various aquatic creatures, including fish, shrimp, crabs, and insect larvae. Additionally, white tree roots extended from the ceiling like stalactites, creating a unique and thriving ecological environment.
Another captivating feature of the Sandiaoling Eco-Friendly Tunnel is its seamless integration of water and light, enhancing its natural beauty. To highlight this interaction, the designer created a 0.5 cm-deep waterway along the tunnel floor, creating a reflective surface that captures and amplifies the surrounding light and scenery. It creates a stunning and mirror-like reflection that echoes with the verdant mountains of Sandiaoling at the tunnel’s entrance.
Additionally, a cantilevered pool was constructed to extend the visitor’s line of sight toward the Keelung River, symbolizing the original railway bridge that once stood there. From this vantage point, visitors can witness the striking view of double-track trains passing on the opposite side of the river.
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