The Viennese Military Transport is a train that travels from Vienna to Istanbul via Belgrade. It is transporting mechanical soldiers of the Austro-Hungarian Empire and is the only method of travelling to Belgrade in the game. The journey costs no money but will require bribing a guard at the station to the tune of £200.
In order to access the Military Transport in Vienna, Passepartout must first aquire the Zauberflote from Herr Danzer and then use it to interrupt the program of mechanical soldiers marching by the Ringstaße at night. After being chastised by a solider, Passepartout learns of the Military Transport's route and can suggest it to Fogg. The Military Transport's route night also be overheard from a group of soldiers if Passepartout retires to a bar during the night after the "steam orchestra's" performance, provided that he attended it beforehand.
The journey to Belgrade is mostly uneventful given that Passepartout and Fogg are the only human passengers aboard.