Carriage of small electric vehicles in Hamburg HOCHBAHN subway vehicles

Fire protection assessment

Pedelecs and e-scooters are emission-free battery-powered electric vehicles that can make a meaningful contribution to climate-friendly mobility. They are particularly suitable for the so-called "last mile" for bus and train users. Since 2019, it has therefore been generally permitted in Germany to take these mostly small and partly foldable means of transport on public transport vehicles.

However, the powerful lithium-ion batteries that are often installed pose the risk of "thermal runaway" if they heat up too much. In the recent past, this has led to several serious fires in rail vehicles worldwide.

For this reason, HOCHBAHN commissioned STUVAtec to investigate the extent to which being carried in Hamburg subway vehicles increases the risk of fire. In particular, it was to be investigated whether the release of heat from a burning small electric vehicle could cause the fire to spread to the subway vehicle.

In a comprehensive investigation, STUVAtec compiled an overview of previous fire incidents and determined the resulting hazards for passengers in public transport vehicles. It was found that, despite the relatively low probability of a fire occurring, the Hamburg subway system with its many long tunnels, relatively narrow vehicles and segregated carriages is not recommended for electric scooters. The risk of damage to health, particularly due to the possible explosion-like development of smoke, is considered too high.

As a result, Hamburger HOCHBAHN has temporarily banned the use of small electric vehicles on the subway from August 2023. The ban only applies in the Hamburg U-Bahn and not in the S-Bahn.

Pedelecs and e-wheelchairs, which have higher safety standards, are not affected by the ban. HOCHBAHN will analyse the issue again as soon as comparable normative specifications are also available for e-scooters.