Regionaltangente West: New cross-connection for the Rhine-Main rail network

The Regionaltangente West (RTW) is one of the most significant infrastructure projects in the Rhine-Main region. The project will establish a radial rail link between the western districts of Frankfurt and the surrounding area, complementing the existing S-Bahn network.
Frankfurt RTW light rail

The new line will connect cities such as Bad Homburg, Eschborn, Bad Soden, Frankfurt Airport, Neu-Isenburg and Dreieich directly, meaning passengers will no longer have to travel via Frankfurt's busy main station.

As part of a comprehensive framework agreement, Ramboll was commissioned to provide technical consulting services for the rail systems technology. This includes signalling and safety technology, traction power and catenary systems, lighting and safety technology, as well as telecommunications and information systems.

These services cover a wide range of disciplines and processes throughout the project, including initial assessments, support with technical queries relating to the rail systems technology, and assistance with operational and commissioning queries until RTW operations commence.

Overcoming complex technical challenges

RTW operations will be carried out using modern dual-system vehicles that can run on both railway lines and the light rail network. This intermodal challenge requires highly complex technical infrastructure, including modern control and safety technology, overhead line systems, and transition systems between different power and train protection systems.

The project will cover a 52 km route with 28 stops (including 12 existing S-Bahn stations) when it reaches its final stage and is scheduled for gradual implementation from 2028. Wherever possible, RTW will utilise the existing network, filling gaps with new rail infrastructure where necessary. The project is being financed by the federal government, the state of Hesse, and the relevant municipalities at a cost of around €1.8 billion.

Sustainability measures and benefits

The Regional Tangent West makes an important contribution to the sustainable mobility transition in the Rhine-Main area. It largely uses existing rail infrastructure thereby reducing its impact on the surrounding environment and minimising resource consumption.

The use of electric vehicles and innovative construction technologies reduces emissions even during the construction phase, while targeted measures such as reforestation and landscape conservation ensure the protection of flora and fauna.

With direct, transfer-free connections, for example to Frankfurt Airport, RTW makes it easier to switch from private transport to rail. It also reduces traffic-related CO₂ emissions and improves accessibility to workplaces and residential areas. In this way, it contributes to improving quality of life, economic development, and resource-efficient urban and regional development.

RTW in numbers

  • : 52 km

    total length of the new tangential railway line

  • : 28 stops

    12 of which connect to existing infrastructure

  • : €1.8 billion

    Investment in the expansion of sustainable regional mobility

Re­lated pro­jects

  • Enabling rural mobility: frequent rail service in the Neckar-Alb region

    The 16 km Echaztalbahn railway in southwest Germany is being revitalised with a regular 15- to 30-minute interval service. The project includes the development of an innovative topography solution and sustainable rainwater management.

    Zweckverband Regional-Stadtbahn Neckar-Alb
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