What were the results of the military campaign in 1914? What were the reasons for the transition to “positional” war?

By the end of 1914, all the belligerent countries in Europe had gone over to trench warfare. This is noticeable on the western front after the battle on the Marne River and on the eastern after the Warsaw-Ivangorod operation, and even in the Balkans after the battles for Belgrade. The transition was associated with autumn and winter thaw, with losses in the first months of the war with the depletion of ammunition and the death or injury of many regular officers.

By the end of December 1914, the Germans controlled part of northern France and part of the western Polish lands within the Russian Empire, from the city of Czestochowa to Lodz.

The army of the Russian Empire was able to take control of Austrian Galicia.