Stuttgart 21: A Visionary Rail Hub and Urban Transformation Project
Main Station Stuttgart in Germany
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Stuttgart Main Station in Germany - Project Entry 2005 Europe
The light eyes are evenly distributed above the platforms, guaranteeing that the station hall has an adequate supply of natural light for up to 14 hours a day.
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Stuttgart Main Station in Germany - Project Update March 2018
Formwork for chalice-shaped concrete pillars in Stuttgart. Photo: Achim Birnbaum Architektur Fotografie.
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Stuttgart Main Station in Germany - Project Update March 2018
Construction of chalice-shaped "light-eyes" concrete pillars in Stuttgart in progress. Photo: bahnprojekt-stuttgart-ulm.de
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Stuttgart Main Station in Germany - Project Update October 2015
The 27 actual pillars which will support the roof of the track hall will be 8 times larger. Image: courtesy Jan Reich.
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Stuttgart Main Station in Germany - Project Entry 2005
The surface-penetrating “light-eyes” are the key characteristic of the design for the loadbearing structure.
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Stuttgart Main Station in Germany - Project Entry 2005 Europe
The new station will link two parts of the urban fabric that have previously been divided.
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Stuttgart Main Station in Germany - Project Update October 2015
The new railway lines will run east-west, replacing the current configuration of terminating lines that arrive from the north.
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Main Station Stuttgart in Germany - Project Entry 2005
The supporting structure of the station hall is a vaulted, seamless concrete shell structure. The vault system is divided into 28 equal modular elements, the chalice supports, between the four platforms and the long outside walls.
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Main Station Stuttgart in Germany - Project Update October 2015
A prototype of a chalice pillar is being tested. Image: courtesy Jan Reich.
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Main Station Stuttgart in Germany - Project Entry 2005
Instead of north-south, the new tracks will be aligned on an underground east-west axis – freeing up enormous space for the city.
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Global Holcim Foundation Awards Ceremony 2006 – Bangkok, Thailand
Presentation of the Global Holcim Awards Gold 2006 trophy to Christoph Ingenhoven (holding trophy aloft) celebrating with team members.
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Regional Holcim Foundation Awards Ceremony 2005 Europe – Geneva, Switzerland
Winner of the Holcim Awards 2005 Silver for Europe, Christoph Ingenhoven for Stuttgart Main Station, Stuttgart, Germany.
AwardsGold2005–2006Global
AwardsSilver2005–2006Europe
Winner of the inaugural Global Holcim Awards Gold (2006), the Stuttgart 21 project reimagines the city’s main railway station by placing it underground—liberating valuable land for urban regeneration and uniting the structural with the natural.
By
Christoph Ingenhoven - Ingenhoven und Partner Architekten, Dusseldorf, Germany
The design is led by Christoph Ingenhoven of Ingenhoven und Partner Architekten, based in Düsseldorf, Germany. Commissioned by Deutsche Bahn, the project includes a new high-speed rail line running through a tunnel perpendicular to existing tracks. Construction began in 2015 and will culminate in the creation of a vast new urban quarter at the heart of Stuttgart.
Main Station Stuttgart
Project authors
Christoph Ingenhoven
Ingenhoven und Partner Architekten
Germany
Project Summary
Reconnecting City and Landscape
The existing central station, a terminus built by Paul Bonatz, had long constrained the growth of Stuttgart’s city centre due to its location in a narrow valley. The new design addresses this by removing surface rail barriers, enabling urban expansion, and reconnecting previously divided parts of the city. The project proposes to stretch the adjacent Schlossgarten park over the subterranean station, blending infrastructure and landscape. Natural light will pour into the station hall through distinctive circular "light eyes", forming a monumental and energy-efficient space.
The innovative shell roof structure—only one hundredth the height of its span—uses minimal material while delivering maximum performance. The station is designed to operate as a "zero-energy building" requiring no heating, cooling, or mechanical ventilation.
Stuttgart Main Station in Germany - Project Update October 2015
The 27 actual pillars which will support the roof of the track hall will be 8 times larger. Image: courtesy Jan Reich.
Designing a New Urban Identity
More than a transit point, the new station forms a civic space. With 420-metre-long platforms, integrated plazas, and walkways, it establishes a new pedestrian axis between Stuttgart’s historic core and the future urban district. The preserved Bonatz building becomes an entry point to this reimagined hub, reconfigured with restaurants, shops, and open interior levels that connect old and new elements in a seamless architectural dialogue.
Led by Christoph Ingenhoven, the design embraces spatial continuity and sustainability, aiming to strengthen collective values around public space. By encouraging walking, social gathering, and public transport use, the station fosters a new sense of civic identity and environmental stewardship. As the city expands, the extended castle gardens will serve as a vital green lung for residents and visitors alike.
Main Station Stuttgart in Germany - Project Entry 2005
The supporting structure of the station hall is a vaulted, seamless concrete shell structure. The vault system is divided into 28 equal modular elements, the chalice supports, between the four platforms and the long outside walls.
Strategic Impact and Community Benefit
Stuttgart 21 offers long-term benefits across social, economic, and cultural dimensions. The underground transformation will catalyse the emergence of a vibrant new city district while improving the efficiency of Europe’s high-speed rail network. By linking areas that were once divided, the station enhances social cohesion and opens up new opportunities for recreation, communication, and generational connection.
The project also exemplifies a progressive urban ethos—avoiding nostalgia while celebrating heritage—and sets a benchmark for sustainable infrastructure that adapts to the challenges of climate, mobility, and densification.
Stuttgart Main Station in Germany - Project Entry 2005
The surface-penetrating “light-eyes” are the key characteristic of the design for the loadbearing structure.
Current Status and Timeline
Testing Phase (Late 2025): Comprehensive system tests will begin, including infrastructure, digital control, vehicles, and staff operations, to ensure a seamless launch.
Main Station Opening (December 2026): The new underground Stuttgart Hauptbahnhof and renovated Bonatz building are set to become operational.
Stuttgart Airport Station (December 2026): A long-distance rail hub at the airport will boost regional connections to Ulm and Tübingen.
Gäubahn Line Connection: Construction on the link via the airport to the Gäubahn is not expected before 2026, with possible completion by 2032, depending on federal budget approvals.
Project Author
Christoph Ingenhoven
Ingenhoven und Partner Architekten
Germany
Jury Appraisal
Innovative Integration Across Disciplines
The project is highly commended for its innovative integration of material, structural, and product research. It delivers a straightforward yet sophisticated response to reclaiming lost urban territory, while advancing sustainable design practices. The efficient use of technology is combined with intelligent resource management, creating valuable opportunities for cross-disciplinary knowledge transfer across architecture, planning, landscape design, civil engineering, urban development, and environmental engineering.
Environmental Responsibility and Knowledge Sharing
A significant achievement of the project lies in its long-term environmental impact. By dramatically reducing energy consumption, it contributes meaningfully to resource conservation while also raising awareness about sustainability among a broad range of stakeholders. The project promotes dialogue on municipal sustainability and highlights the importance of interdisciplinary collaboration, reflecting a strong commitment to both the flow of energy and the productive exchange of ideas.
Stuttgart Main Station in Germany - Project Update March 2018
Formwork for chalice-shaped concrete pillars in Stuttgart. Photo: Achim Birnbaum Architektur Fotografie.
A New Civic Presence for the City
This is an exemplary scheme for recovering urban territory and giving it new spatial significance. The station creates a landmark civic space that is culturally and functionally rich, while enhancing the overall urban experience. Its contribution spans several fields, offering a model that blends architecture, urban and landscape design, and engineering into a cohesive vision for modern infrastructure.
Ethical Commitment and Cultural Sensitivity
Equally important is the project’s ethical and social orientation. It champions the creation of socially viable environments grounded in cultural values. The “light eyes” are a particularly inspired feature, serving both as luminous design elements and practical daylighting tools that connect the public realm above with the infrastructure below.
Efficient, Flexible, and Future-Focused
By maximising the use of natural energy resources and recycling existing structures, the project proves itself to be both environmentally and economically sustainable. Its flexible design allows for future adaptation, supporting a range of evolving functions and needs. The infrastructure achieves a careful balance between natural and built environments, demonstrating aesthetic finesse and a deeply contextual approach to urban renewal.
Project Updates
November 09, 2018 | Symposium Report | Hannover, Germany
Architecture as a Bridge Between City and Future
In a feature article by the Holcim Foundation, architect Christoph Ingenhoven reflects on the transformative vision behind Stuttgart Main Station. Designed as part of the Stuttgart 21 project, the station exemplifies how architecture can bridge the practical demands of infrastructure with aspirations for a more connected, sustainable, and people-centred urban future. The design reclaims land for public use, integrates nature and movement, and redefines the station as a vibrant civic space—serving both functional mobility and broader social and environmental goals.
March 15, 2018 | Project Update | Stuttgart, Germany
The Pillars of Progress: Stuttgart Main Station Takes Shape
A recent update from the Holcim Foundation highlights the steady construction progress of Stuttgart Main Station, focusing on the installation of its iconic load-bearing "chalice" columns. These sculptural concrete forms not only support the vast shell roof but also serve as skylights that channel natural light into the subterranean platforms. As the structural core of the station emerges, the project continues to embody its vision—uniting architectural elegance with engineering precision to create a new benchmark for sustainable, people-oriented infrastructure.
October 16, 2015 | Project Update | Stuttgart, Germany
Main Station Stuttgart Moves Closer to Completion
In this project update from the Holcim Foundation, the Stuttgart Main Station continues its transformation into a pioneering piece of sustainable infrastructure. With the majority of the striking "light eye" columns now in place, the shell roof is taking shape, demonstrating both structural efficiency and architectural ambition. The station’s subterranean design reclaims urban space above while inviting daylight below—reinforcing its role as a future-focused transport hub and civic landmark within the Stuttgart 21 development.
April 25, 2006 | Media Release | Bangkok, Thailand
Global Holcim Foundation Awards Gold for Stuttgart Main Station
The Stuttgart Main Station project, designed by Christoph Ingenhoven, was awarded the Global Holcim Awards Gold for its groundbreaking approach to sustainable urban infrastructure. Recognised for placing the rail station underground to free up valuable city space, the project combines engineering innovation, environmental performance, and civic design. Celebrated as a model for future infrastructure, it demonstrates how large-scale construction can respond to ecological, social, and spatial challenges while creating lasting public value.
September 16, 2005 | Media Release | Geneva, Switzerland
Stuttgart Main Station Wins Silver at Holcim Awards Ceremony in Geneva
At the Holcim Foundation Awards ceremony held on September 16, 2005, in Geneva, Switzerland, the Stuttgart Main Station project was honoured with the Holcim Awards Silver for Europe. The jury praised the project for its visionary approach to transforming a major infrastructure node into a sustainable, people-oriented civic space. Designed by Christoph Ingenhoven of Ingenhoven und Partner Architekten, the station places rail lines underground, enabling the recovery of urban land for public use and ecological regeneration. The award recognises the project's exemplary integration of architectural innovation, structural efficiency, and environmental stewardship at the city scale.
The continuous form of the shell-type concrete roof creates a highly efficient load-bearing structure, subject only to pressure loads, with a structural height as little as 1/100 of the span. The use of advanced high-strength concrete and cement grades allows material properties to be selected so that the durable exposed concrete surfaces also form the building’s final finish.
The project was selected through a three-phase competition involving a participatory process, with the design subsequently presented to the public. Schlossgarten Park—Stuttgart’s most important public green space—extends seamlessly over the new station, with the roof forming an integrated part of the landscape. The 420-metre-long platforms are echoed above ground by the circular “eyelet” skylights, visually linking the platform level with the park. As a whole, the station—with its plazas, walkways, and platforms—establishes a new central public space and social meeting point, creating a continuous pedestrian connection between the Stuttgart 21 development and the existing city centre. The listed historical Bonatz building is thoughtfully integrated into the station’s functions.
By harnessing natural energy resources, the station achieves a high level of visual and thermal comfort with minimal primary energy consumption. With an average daylight quotient exceeding 4%, supplementary lighting employs a refined balance of direct and indirect light, achieving a specific connection value of just 3–9 W/m². Natural ventilation and air extraction, driven by thermal air flow and natural draughts, generate a platform air speed of 1.0–1.5 m/sec. High comfort levels are maintained without thermal energy input, with mean felt temperatures of 20–22°C in summer and 5–8°C in winter. Approximately 20% of Stuttgart’s electricity is sourced from ecological energy.
The building’s volume is minimised, with the reusability of formwork elements and the prefabrication of modular components contributing to efficient and cost-effective construction. The station’s functional requirements are met through modular, replaceable finishing elements—ensuring durability, adaptability, and a long service life.
The station’s distinctive, nature-inspired form establishes a lasting aesthetic identity for the structural system. The integration of public pedestrian pathways with the “concealed” architecture complements the surrounding urban fabric, creating a harmonious dialogue between spatial simplicity and refined visual experience.
