Please note that this post was originally written in December 2007. Since then there has been a further round of changes - see my later post about timetable changes in December 2008.
December 9th marked the introduction of new train timetables across Europe, with some important changes to international routes in the Balkans. After spending some time trying to reconcile conflicting sources of information, my current understanding of some of the changes in the 2007/2008 timetable is outlined here.
The "Olympus Express", which used to run from Ljubljana to Thessaloniki via Zagreb, Belgrade, and Skopje, will now run from Ljubljana to Belgrade only. This means that there is no longer any direct overland connection between Slovenia/Croatia and Macedonia/Greece. I've travelled on this train several times, and will miss it even though it always seemed to be late: I liked the idea of travelling from the Aegean to the edge of the Alps in a single journey. Of course it is still possible to do this trip by rail, but a change of trains in Belgrade is now required. The change also means that there is only a single daily train between Greece and the Republic of Macedonia - further weakening the already poor public transport links between those two countries.
Thessaloniki may now be less well connected to Croatia and Slovenia, but connections to some other parts of Central and Eastern Europe have improved. The "Hellas Express" continues to run every day from Thessaloniki to Belgrade, albeit with a slightly different schedule. This train will also carry through carriages to Budapest (23 hours from Thessaloniki), Vienna (27 hours), and Prague (32 hours). This is the first time in many years that it is possible to travel to these cities without a change of train on the direct route through Serbia, rather than looping around through Romania.
For truly hardcore train buffs, the Hellas Express will also have a through car to Kiev and Moscow - an epic journey of (gulp) 66 hours.
On the Belgrade-Bar line, the so-called "business train" has been withdrawn for the moment, and will now run during the summer season only. This leaves just one daytime train and one night train running year round on the route from Bar to Belgrade's main station. There is an additional night train from Bar to Novi Sad and Subotica which calls at Novi Beograd.
It's worth noting that at the time of writing, online information about Balkan train schedules is a bit of a mess. The Greek and Macedonia rail operators have not updated their websites to reflect the new timetables. It also appears that the European Rail Timetable on the Die Bahn and Austrian Railways sites has not been updated with complete information about trains through Greece or Montenegro. The nightly train from Bar to Nis seems to be missing from all online timetables, but I'm told that it still runs all year round.
I have updated the page about travelling from Croatia to Greece to reflect these changes.
All that remains is for me to wish all the readers of Balkanology a Happy Christmas and New Year - and happy travels in 2008.