Budapest-Subotica-Beograd-Nis (train)
Route: From Budapest to the frontier station of Kelebia; By bicycle across the border to Subotica,
the first station in Serbia. From Subotica to Beograd with another train. The following day I took an afternoon train to Nis.
From Nis (Niska banja) i cycled to the bordertown of Dimitrovgrad and the next day to Sofia.