9 km of public space. Radbahn is a project initiated in 2014 by the association 'Paper Planes' and proposed to the city of Berlin.

The idea is to repurpose the space beneath the U1 viaduct, the city's oldest underground line spanning 9 km, into a dedicated area for slow mobility. In 2022, fabulism, in collaboration with Nuko, won the tender to design the first 200-meter test section. 

A new space for all. The project is located in the historically diverse and vibrant district of Kreuzberg.

The islands concept. Developed during online workshops, it is based on the assumption that various users and functions will coexist along the cycle path.

Activities such as sitting, playing, or events will occur on the "Interaktionsinsel." The second island, called the "Radinsel," is designed primarily for cyclists, featuring small infrastructures and custom-made objects.

From parking lots to linear park. Between the two islands, the central strip will be transformed into a green linear park.

More than 4000 plants. The green area is designed in a multifactorial way.

The soil is treated in eight different ways, ranging from complete removal of the existing soil to partial maintenance and experimentation with various substrates and treatments. This diversity in soils is matched by a diversity in vegetation, with 4,000 plants introduced to the area. Factors such as sun exposure, water permeability, pollution levels, proximity to roads, and presence of animals and insects contribute to making the space an ecological infrastructure.

Reuse of materials. The reddish concrete paving that covered the former parking niches provided a valuable resource for the redesign of the project.

Smart infrastructure. A large collection of objects has been specially designed to create an interactive and inclusive public space.

These include newly designed benches and sound objects for children, a spacious wooden tribune for visitors to relax on, a repair station, a tube dispenser, and a specially designed inclined litter bin for cyclists.

Water as a resource. The green strip is designed as a climate-adapted space.

Planted areas are subtly contoured to collect and retain rainwater5 during heavy downpours, facilitating slow evaporation and supporting natural tree development during dry periods. Additionally, a phyto-purification system, developed in collaboration with the Technical University of Berlin, has been installed to monitor and improve the water quality flowing from the viaduct.

Formerly used as a car park, the site is now being transformed into a new urban green space open to the city. The project regenerates the vacant space under the viaduct into a hybrid area where slow mobility and nature can coexist, creating a new public space or, more precisely, a covered linear park.

With biodiverse plantings on the sides, it enhances the cycling experience by bringing nature into the city. The former car park surfaces will be converted into permeable areas, open to plant colonization.with biodiverse plantings

The concrete blocks from the car parks were reused to create the permeable surfaces of the islands, while the kerbs were repurposed as paths through the vegetation.