With alliance contracts, Deutsche Bahn is embracing a new form of collaboration – and Rhomberg Sersa is actively helping to shape it.
An integrated team from an early stage, a shared goal and decisions based on the “Best for Project” principle: this is precisely what the Rail Partnership Model stands for. Two pilot projects in Baden-Württemberg demonstrate just how effective this model can be.
Alliance contracting models represent a new approach to delivering complex infrastructure projects. Instead of working under conventional individual contracts, clients, designers and contractors collaborate under a joint multi-party agreement. The focus is not on individual areas of responsibility, but on working towards shared schedule, cost and quality objectives.
With its Rail Partnership Model, Deutsche Bahn has specifically adapted this approach to large and demanding rail infrastructure projects. The early involvement of all key parties creates the basis for coordinating construction processes, logistics, line closures and technical solutions from the outset, as well as allowing them to be optimised holistically.
The model also sends a strong commercial signal: target costs are defined jointly, while opportunities and risks are shared between the partners. This creates transparency, strengthens trust and is visibly driving cultural change in railway construction.
The Rhomberg Sersa Rail Group is involved in two pilot projects in Baden-Württemberg as part of this forward-looking approach: the Gäubahn North upgrade and the Residenzbahn project.
Gäubahn North upgrade
The Pfaffensteig Tunnel plays a key role in the Gäubahn North upgrade. At approximately 11 kilometres in length, it will be Germany’s longest tunnel. It will connect Stuttgart Airport with Böblingen and link the Stuttgart–Zurich route to Stuttgart’s new central station.
Under the Rail Partnership Model, the planning was advanced in a remarkably short period of time. Following the planning phase from 2023 to 2025, preparatory work for the tunnel excavation has already begun, with commissioning scheduled for 2033.
Together with its joint venture partner Swietelsky Bau GesmbH, RSRG is responsible for key elements of the project. This includes the entire track superstructure, comprising slab track and ballasted track, the 50 Hz electrical systems, the mechanical tunnel equipment and the coordinated installation of cables.
Residenzbahn
Deutsche Bahn is also relying on the strength of the Rail Partnership Model for the Residenzbahn project. The project combines measures along the Söllingen–Pforzheim section and at Wilferdingen-Singen and Pforzheim stations in order to remove barriers, increase capacity and avoid several separate construction sites in quick succession.
The effectiveness of the alliance model is particularly evident in the planning of the railway bridge over Luitgardstrasse in Pforzheim: a detailed and robust solution was developed within a short period of time, reducing the construction period, traffic disruption and use of resources.
The planning phase has been under way since 2025 and is scheduled to continue until 2028, with construction expected to be completed by around 2030. Together with REIF Bauunternehmung GmbH & Co. KG, Rhomberg Sersa is responsible for the transport infrastructure, including earthworks and civil engineering, platforms, track superstructure, roads, paths and public spaces, as well as cable duct construction and drainage.
For RSRG, alliance contracts are far more than simply a new form of contract – they are a powerful means of delivering infrastructure projects collaboratively, safely, efficiently and with a clear focus on the future.
