The wigned wheel symbol plus DR (stands for Deutsche Reichsbahn) on your lamp is definifely railway use (whereas DB stands for Deutsche Bahn).
DR was the railway organisation of Germany before end of WW2, Deutsches Reich, after end of WW2 and the divison of remaining germany, the railway organsiation in eastern germany, later DDR (GDR) continues using the name DR for the railway system whereas in the western part it was named Deutsche Bundesbahn, using DB as abbreviation.
After 1994 both state railways (DR and DB) melted to Deutsche Bahn AG, the abbreviation still remained DB
(just seen that Christina was quicker than me...)
P.S. the material marking on your lamp AlMg... is rare, never seen this before. The lamps I know are made of brass or just mild steel, but not of Aluminum.
As the Swastika is missing, the lamp was made either before approx. 1933 or after 1945 for the DR in eastern Germany.