German rail operator Deutsche Bahn intends to keep around 20% of its long-distance services running during a 24-hour-long strike that is set to begin on Thursday evening, a spokesperson said.

The strike by Germany's GDL train drivers' union will start at 6 pm (1700 GMT) for freight traffic and at 10 pm for passenger trains, ending on Friday at 10 pm, the union said on Wednesday.

"We are in the process of drawing up an emergency plan," Deutsche Bahn's spokesperson said, adding however that the rail operator will not be able to accommodate everyone who wanted to travel on its trains as a result of the reduced capacity.

Already purchased tickets for rides affected by the strike can still be used for travel on Thursday before the strike begins and after its end, during the weekend or at a later point in time, the spokesperson added.

The train drivers' union had already held a 20-hour strike at Deutsche Bahn in mid-November. Passengers should not worry about their Christmas travel plans, though, according to GDL boss Claus Weselsky.

"This strike is the last one for this year," he said, adding that the union has initiated a ballot for an indefinite strike, the results of which are expected to be available before Christmas.

Weselsky anticipates longer strikes in January. (Reporting by Susanne Neumayer-Remter and Christine Uyanik, Writing by Nette Nöstlinger; Editing by Kim Coghill)