The railway wants to use biofuel on the last long-distance routes with diesel locomotives in the future.
"By 2025, we will convert the last remaining almost two percent of the diesel-powered long-distance routes to biofuel and thus set a further example for climate protection," said Stefanie Berk, Head of Marketing at DB Fernverkehr, on Wednesday.
These are the routes Erfurt-Gera and between Immenstadt and Oberstdorf.
According to the information, 100 percent green electricity is used on all other long-distance routes.
Since this Wednesday, the diesel trains of the Sylt Shuttle and the Sylt Shuttle Plus between Niebüll on the Schleswig-Holstein mainland and Westerland on Sylt have been refueled with biofuel.
According to Bahn, this saves around 7,500 tons of carbon dioxide every year.
The fuel used is produced exclusively from biological residues and waste.
No specially cultivated biomass is used, competition with food and feed production is excluded.
"Above all, this is a valuable contribution to environmentally friendly tourism in the Wadden Sea National Park," said Schleswig-Holstein's State Secretary for Transport, Tobias von der Heide (CDU).
The next important step is the complete electrification of the so-called Marschbahn route to Sylt.
"Because this is the only way we will be able to travel completely emission-free in the long term and, on top of that, significantly reduce travel times."
According to their own statements, just 61 percent of the track network was electrified in 2020.
Diesel locomotives are still driving around in many places.
By 2030, 75 percent of the routes should be electrified.
The Pro-Rail Alliance has long been demanding higher speeds from the railways.
"Only with an accelerated expansion of e-mobility on the tracks can the federal government achieve its goal of operating at least 70 percent of the railway lines in Germany electrically by 2025," said the Pro-Rail Alliance last year.