Subterra, the lead contractor for Prague’s Metro D expansion, has officially contracted German manufacturer Herrenknecht to supply high-precision tunnel boring machines (TBMs) for the line’s latest segment. According to Subterra CEO Ondřej Fuchs, the decision to opt for German technology over Chinese alternatives prioritizes long-term service reliability and strict adherence to European safety standards for the 30-billion-CZK project.
Why did Subterra choose German TBMs over Chinese alternatives?
While Chinese TBM manufacturers offered prices approximately 10% lower than their German counterparts, Subterra ultimately selected Herrenknecht for its proven track record in the Czech market. According to Fuchs, the company’s history with Herrenknecht—which previously supplied machines for the Metro A extension and the Ejpovice railway tunnel—outweighed the initial cost savings. The decision hinges on the specialized service support and the integration of safety protocols required by current Czech regulations, which the company deemed more critical than the lower upfront capital expenditure.
The TBMs used for the previous Prague Metro A extension were famously named “Adéla” and “Tonda” by local children. Despite their effectiveness, Subterra opted to purchase new machines for the Metro D project due to a 13-year delay in the project’s timeline and the resulting obsolescence of older safety features.
How will the new tunnel boring machines impact the construction timeline?
The new TBMs are expected to arrive within six months of the order, with the second machine following roughly one month later. According to Subterra, the current project scope includes 9.6 kilometers of TBM-bored tunnels and 2.6 kilometers of conventional New Austrian Tunneling Method (NATM) excavation. The updated construction schedule now targets a 2032 completion date. This adjustment accounts for the extended preparation period and the need to synchronize the handover between different project phases.
Can these machines be reused for future Metro D phases?
The TBMs are designed to be modular and adaptable to similar geological conditions, meaning they could potentially be utilized for the upcoming Pankrác to Náměstí Míru segment. Subterra confirmed that while the tender conditions for that section remain unknown, the geological profile is sufficiently similar to allow for reuse following standard mechanical refurbishment. This potential for reuse represents a strategic asset for the contractor in future bidding processes.
Comparison: Excavation Methods for Metro D
| Method | Total Length (km) |
|---|---|
| TBM (Tunnel Boring Machine) | 9.6 km |
| NATM (Conventional) | 2.6 km |
When tracking major infrastructure projects, look at the “valorization” clauses in public contracts. Subterra’s agreement includes inflation-linked adjustments based on national statistical data, which protects the project budget from extreme material cost volatility over the six-year construction window.
Frequently Asked Questions
- What is the total budget for the Olbrachtova to Nové Dvory section?
The project is estimated to cost approximately 30 billion CZK. - How deep will the Metro D stations be?
Depths vary by station; for example, the Nemocnice Krč station will have its tracks located 17 meters below ground level. - Will the construction affect surface traffic?
Yes, the Nádraží Krč station is a surface-level build, while others will be excavated from the surface or via tunnel boring, necessitating localized site management.
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