When the French and Belgians occupied the Ruhr in January 1923, in order to take coal and steel back to their own countries, there was passive resistance, which later became known as the Battle of the Ruhr ("Ruhrkampf"). In Erkelenz this passive resistance was carried out especially by railwaymen, in the course of which the Belgian secret police expelled 14 families, including small children, who had been reported by narks. They were abandoned, in some cases using force, in remote places at night and in fog.