Hi there !
I’m in trouble to find informations about the feasibility of this connection, since I coudn’t find any information on the Interrail or on the Serbian website. My full plan is to go from Grenoble (France) to Kolasin (Montenegro).
Thanks for the help,
Raclette
There suposed to be atleast one train per day (in Summer 2 per day) but actual i heard that the trains are currently not in operation due Trackworks on the Serbian side 
Edit: As i said there are currently no trains between Zagreb and Beograd :/
Option B Zagreb - Split, Bus or Ferry to Dubrovnik and then by bus to Montenegro 
the train Bar - Podgorica- Belgrade is in operation
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.