Monument to....?

Many times I have passed by these columns which stand on a knoll on an otherwise flat area in the park next to Hotel Jugoslavija. I finally walked up the knoll and found a section of train tracks! I asked a passer-by what these were, and she told me they were all that was left of an old train station. There was no plaque and my Googling was to no avail. I fiddled with the contrast and highlights here, for it was such a dreary photo (and day.)