A problem with a communications system forced Germany’s railway system to halt all trains late Tuesday, leaving passengers stranded across the country.

The main national railway operator, Deutsche Bahn, said all trains were being held at stations because of a nationwide problem with the GSM-R digital communication system, which is used for internal communication on the railway network.

Deutsche Bahn said in a statement at midnight, 1½ hours after it first announced the problem, that the cause had been identified, but did not specify what it was.

It said that technicians “are working intensively on a solution”.

It did not specify how long that might take or say how many trains or passengers were affected.

The Bild newspaper quoted Deutsche Bahn CEO Evelyn Palla as saying that “we are now trying to get the trains into stations so that travellers can disembark”.