Karl Josef Franz Feiler started working in the Eisenbahnministerium (Ministry of Railways) in 1907. After the First World War and the completion of his history doctorate he was promoted to the position of railway archive historian. In 1924 he became head of the transport archive, as it was now called, in the Staatsamt für Verkehrswesen (State Transport Office) before being appointed director a year later of the Eisenbahnmuseum (Railway Museum). He was a member of the Deutsche Verkehrswirtschaft and, according to the Gau headquarters in Vienna, was a supporter of the NSDAP during the period of its prohibition. In September 1943 he was awarded the Kriegsverdienstkreuz 2. Klasse (War Cross of Merit 2nd Class) for having liquidated the documentation and planning department in Laibach (Ljubljana) in 1942 and transferring them to the Deutsche Reichsbahn.

After 1945 Feiler was deemed to be politically unincriminated as he had not been a member of the NSDAP and had been an applicant only for a short time for the Betriebs-SA des Ministeriums für Handel und Verkehr (in-house SA in the Ministry Trade and Transport). Following the incorporation of the transport archive in the Österreichisches Staatsarchiv (Austrian State Archives) in 1947, he was put in charge of the new department, while Melanie Marsch, director of the railway library in the Verkehrsministerium (Ministry of Transport), became director of the Eisenbahnmuseum in 1947 for the next four years. Feiler retired at the end of 1952.