Swissmetro is a magnetic transportation system running inside partially evacuated underground tubes. The system could achieve speeds between 300 and 500 kilometres per hour, which comes close to the lower range of short-haul air traffic. Some experts see Swissmetro as an environmentally very attractive alternative to both air and ground high-speed transportation, since noise pollution and energy consumption as well as negative impacts on residential areas and the landscape could be substantially lower.

The idea of the Swissmetro dates back to the 1970s and has since been studied by scientists at the Swiss Federal Institute of Technology in Lausanne (EPFL). In 1992 the Swissmetro Company SA was founded to collect the funding necessary for further R&D on the Swissmetro.

The Swissmetro was originally discussed as a rapid means of transportation between Swiss metropolitan areas. At present there is a concept called "Eurometro" which studies the potential for a Swissmetro system connecting major European cities.

Technical details

• the most important aspects of the Swissmetro system are:
• Underground infrastructure, consisting of two tunnel tubes of 5 m interior diameter each that in the case of the pilot line between Geneva and Lausanne run at a depth of between 60 and 300 meters.
• Production of partial vacuum in the tunnel tubes (corresponding to the pressure at about 18,000 m above sea level being the traffic altitude of the Concorde) in order to reduce air drag
• The pressurised vehicles are planned to have a length of 80 m, an external diameter of 3.2 m, and a seating capacity of 200 persons. Due to the pressure difference, boarding at stations has to be supported by a sophisticated system of automatic doors and galleries
• The propulsion system for the vehicle is based on linear electric motors, allowing speeds in the order of up to 500 kilometers per hour.
• Magnetic levitation and guidance system (comparable to Maglev)

An extensive study on the environmental impact of Swissmetro has been conducted by the National Research Programme 41 in Switzerland (Ernst, Geisel et al. 2000). Concerning energy consumption the study yielded the following results:

Comparison Swissmetro – Air traffic

On an assumed pilot route Frankfurt-Rome, the primary energy consumption per person kilometer of Swissmetro would be 5 to 10 times less than in air traffic. The exact factor depends both on actual passenger numbers for the Swissmetro and on the efficiency gains in air transportation (that could be as high as 50% in the next 50 years according to some experts). This assessment includes the so called "grey energy" needed to construct the infrastructure. The (electric) energy demand for operation only was calculated to be

0,185 MJ/pkm for an assumed 76.000 passengers/day

0,21 MJ/pkm for an assumed 38.000 passengers/day

Comparison Swissmetro – conventional high speed rail systems

The energy consumption (for operation only) of the Swissmetro would be roughly 50 % less than both in conventional high-speed rail systems (e.g. ICE) and in ground-level Maglev/Transrapid system. This comparison refers to equal speeds.

Influencing factors

The following factors are especially relevant for energy demand of a Swissmetro system:

• Tunnel width: The wider the tunnel tube, the less air drag is encountered by Siwssmetro vehicle. Even if the additional energy for tunnel excavation is included in the calculation, a wider tunnel profile is favourable for energy efficiency
• Degree of evacuation: The less air pressure, the less air drag in the tube. There is however an evacuation limit given by safety considerations.