German trains will completely give up diesel by 2040 and switch to biofuel as the leading alternative, rail operator Deutsche Bahn said Sunday.

"Our 3,000 diesel vehicles will be gradually transferred to running on alternative fuels from this year," Deutsche Bahn Chief Executive Richard Lutz said.

"In addition to the switch to 100% electricity, the gradual elimination of diesel by 2040 is one of our central ecological plans."

The group intends to rely on biofuels, among other things, which are to be produced from leftover and waste materials so that fuel production does not compete with food production.

When it comes to new vehicles, the firm said it would only buy hydrogen or battery-powered engines in the future.

The freight transport subsidiary of Deutsche Bahn, DB Cargo, announced similar goals in mid-January, including the use of so-called dual-power locomotives.

These can switch between conventional diesel and modern electric drive and can thus be used both on electrified tracks and on secondary lines without overhead lines.