A high-speed metro in the Swiss Alps?

EPFL and UNIL are located in Lausanne, the capital of the Swiss canton of Vaud, currently well-serviced by modern transportation infrastructure between regional cities and towns. However, commuters in more remote regions such as the Vaud Alps rely on private vehicles to commute for work, often resulting in expensive and unsustainable long journeys in heavy traffic. Furthermore, within the alpine regions, transportation between ski resorts and villages during the winter mainly relies on private vehicles or buses with long and sinuous routes due to the alpine topography, and roads are at the mercy of winter weather, forcing closures.

One potential solution to these commuter challenges would be to develop a high-speed metro-style rail line through the Vaud Alps connecting to existing inter-city and regional infrastructure. Such a line would not only improve the sustainable transportation options within and between communities in the region but potentially deliver renewable energy benefits, lowering CO2 emissions and enhancing regional tourism.

To explore these and other opportunities, UNIL’s ISTE and EPFL’s LMS labs have joined forces to examine the feasibility of the idea and build on the work of of Rocco Wennubst Pedrini, who has started work on a preliminary study of the project and will join the Jaboyedoff Group at UNIL in February, freshly graduated from civil engineering at TU Delft.

Through the CLIMACT Center, a joint initiative whose mission is to promote system-wide change as well as interdisciplinary and inter-institutional research in the field of climate impact, the aim is to explore key challenges in developing such transportation infrastructure, including boring and tunneling as well as operating high-speed metro-style trains at gradients of up to 12 percent, which would be a world first. The objective of the initial project is to scope out the potential for such a train line. It will involve the creation of a 3D geological model of a proposed route, exploring potential excavation technologies capable of boring and drilling at steep gradients and, the train technologies to travel on such a route. Existing traffic loads, predicted demographic changes in the region and hydrogeological and geothermal models of the area would also be developed and collated with the main objective of exploring energy recovery and emissions savings potentials if the route were to be constructed.

Prof. Jaboyedoff has been pushing for this project for a long time “VAlp Express has its roots in the old dream of linking Les Diablerets to Gstaad via a tunnel under the Col du Pillon, following the route of the Aigle-Sepey-Diablerets mountain railway. The issue nowadays is whether living in the Alps is still viable in terms of energy and economy. Because it would make it possible to travel from Aigle to Villars in 7 minutes and in less than 25 minutes to Château-d'Oex, this metro would become the priority means of transport for the inhabitants of these stations and would bring them together in a single station to promote gentle and diversified tourism, facilitate transport of goods.

VAlp Express is a concept that, if we demonstrate that it has a positive environmental impact in the long term, it can potentially become a Swiss product that can be exported to the mountainous regions of the world. But before reaching such an objective, many skills from EPFL and UNIL will have to be brought together to meet this technical and scientific challenge: civil engineering (tunneling), geology, energy, mechanics (aerodynamics, traction), mobility, etc.

The Climact Center gives us the opportunity to make an initial assessment of the feasibility of this somewhat crazy research project, which I am convinced will grow within our two institutions”.

Sofie ten Bosch, a research assistant in the Laloui Group at EPFL, says that the interdisciplinary nature of the project is perfect for the Climact joint initiative between EPFL and UNIL, and whilst the project is challenging, the potential benefits to the region and as a possible blueprint for other similar projects around the world, is massive.

“We are researching the question, is living in the mountains still sustainable? This is very much a brainstorm and includes areas outside engineering, so this project goes well beyond our lab’s normal scope. We have many stakeholders we need to talk to and collect data from. For instance, how many passengers do we expect based on tourism seasons? How much traffic is there now for tourism and other sectors, can this be reduced, and what is the long-term plan for the region? This, combined with exploring the geology and understanding the limits of current tunnel boring and metro technology, will allow us to understand the gradients and speeds a metro can achieve under alpine conditions,” explains Ten Bosch.

Sustainability is a critical priority in the feasibility assessment of the project. Work will explore potential CO2 reductions, energy production and efficiency improvements, and the possible uses of the tunnel for conveying other types of connections, such as, high-speed communication cables and other infrastructure and goods often challenging to disseminate in the mountains.

The project is a first step in what would be an amazing feat of engineering. If feasible, it may transform alpine living across the world, with the infrastructure developed allowing commuters to avoid landslides and winter snowstorms as well as bringing mountain communities much closer to regional hubs and cities. At the same time, winter tourism, a vital component of the regional economy, will benefit through an enhanced transport system that reduces travel times, lowers emissions, and uses less energy. Such a transport system may therefore ensure regional alpine communities remain viable and economically and environmentally sustainable while slowing the ever-increasing urbanization of our world.