Is this really the collar emblem, or just a lapel pin for the workers to wear on civilian clothing? Most of the insignia (for collar, shoulderboards or caps) from Yugoslavia I have seen had either wire attachment or screw attachment.
The only truly clear image of these in wear I have seen the conductor is wearing one of these on both his left and right lapel. The long pin doesn't feel like something that would easily take to the neck region but these were worn in pairs on the lapels if not the collar itself.
They're certainly not in use today as the uniform doesn't have the grandeur it once had.