Berlin Bahnpost (DE)

From Stamps of the World

Postmarks placed as Ambulant in railway wagons. There were Bahnpost lines from BERLIN to BRESLAU, BROMBERG, CÖSLIN, EISENACH, GÖRLITZ, HALBERSTADT, HALLE, HAMBURG, HANNOVER, LEIPZIG, MAGDEBURG, MINDEN, STETTIN and STRALSUND when the German Empire was created.

Source: Peter Feuser 1983

Postmarks in German Reich

BERLIN-HANNOVER ZUG 209 in 1916.