© Wiener Linien

Vienna’s public transport operator Wiener Linien will introduce ten hydrogen-powered buses on its 39A route from 1 December 2025, marking the city’s first full conversion of a bus line to hydrogen operation.

Context Within Vienna’s Zero-Emission Transport Strategy

The move extends Vienna’s wider shift toward zero-emission public transport, with more than 80% of journeys already made on low-carbon modes such as metro, tram and electric buses. Hydrogen vehicles are expected to play a growing role in near-term refueling demand.

Technical Specifications And Operations

The 12-metre buses, manufactured by Portugal’s CaetanoBus, will be equipped with Toyota 70 kW fuel cells and five roof-mounted hydrogen tanks storing a total of 37.5 kg of fuel. Wiener Linien said the units offer a minimum range of 400 km, enabling day-long operation without refuelling and potential service during night hours. The vehicles house a 180 kW Siemens electric motor and can carry 78 passengers.

Hydrogen Supply And Depot Infrastructure

Hydrogen supply will come from Wien Energie, which plans to produce green hydrogen at the Smart Campus of Wiener Netze using an on-site electrolyser powered by renewable electricity. Refuelling and maintenance will take place at Wiener Linien’s Leopoldau depot, which is already equipped with a hydrogen station.

Demands Of The 39A Route

The 39A line — characterised by short stop spacing, heavy passenger loads and steep gradients — is considered one of the network’s more challenging routes. Gudrun Senk, Wiener Linien’s technical managing director, said drivers had “intensively tested the buses under real conditions” ahead of the launch.

Investment And Broader Industry Implications

Wiener Linien, alongside Austria’s Ministry for Innovation, Mobility and Infrastructure and the European Union, is investing €10.4mn in the purchase and maintenance of the CaetanoBus fleet. The shift to hydrogen makes the 39A route the operator’s twelfth to transition to emission-free vehicles, following a mix of battery-electric and hydrogen models deployed across the city.

The rollout highlights how European transit authorities are assessing hydrogen mobility for routes requiring long daily ranges or lighter vehicle weight. For policymakers and operators, the project provides an additional reference point for the integration of green hydrogen production and refuelling infrastructure into urban transport systems.