SAGASTA took part in the restoration of one of the most remarkable railway lines in the Czech Republic – the cog railway between Tanvald and Kořenov, commonly known as the zubačka. This technical monument is not only the steepest railway line in the country, but also one of the few cog railways of its kind in Central Europe.
A Project for a Technical Monument
SAGASTA prepared the project documentation for the building permit and for construction execution, and also provided author’s supervision. The project was commissioned by Správa železnic. Its aim was the comprehensive repair and stabilisation of the line in the challenging terrain of the Jizera Mountains. The project primarily addressed the repair of the railway superstructure and substructure, as well as bridges, retaining walls and tunnels, all of which had been damaged over time by frost, weathering and extreme rainfall.
All work was carried out with maximum respect for the historic value of the line, which is officially classified as a technical monument. Special attention was given to preserving original design features and characteristic details, allowing the cog railway to retain its authentic appearance.
Restoring Unique Cog-Railway Technology
One of the key elements of the project was the renovation of the Abt rack rail, which enables the line to overcome its extreme gradients. As part of the reconstruction, three special rack turnouts were supplied and tested. The tests confirmed the structural correctness of the design for both standard and full cog-railway operation. The reconstruction also included rock-slope stabilisation, drainage works and the renewal of six level crossings.
The project was led by Chief Engineer Dávid Kuczik, under whose leadership the SAGASTA team of specialists prepared the documentation. The implementation involved the company Tým dopravního inženýrství.
The Return of a Legendary Railway Line
Once the reconstruction is completed, regular and historic trains will run once again on the Tanvald–Kořenov line from 1 November 2025. The reconstruction demonstrates that even a railway line more than a century old can remain a fully functional part of today’s transport infrastructure thanks to modern technologies and thoughtful project preparation.
SAGASTA successfully combined a sensitive approach to a heritage-listed structure with modern engineering methods that ensure long-term, safe operation. The project is not only a contribution to preserving the Czech Republic’s technical heritage but also clear proof that high-quality design work can support sustainable transport and promote regional development.