tomseeley,
We took the train from Brasov Romania to Istanbul several years ago. Yes, it stopped in the middle of the night at the border where we were required to produce our passports and $100 US currency. The sleeping cars were reasonably comfortable, but the compartments are not very secure. Our conductor showed us how to secure the door to our compartment from the inside using a coat hanger. We were treated with more courtesy than other passengers, those not carrying US passports, who were required to leave their compartments while they were searched. Our conductor showed us how to secure the door to our compartment from the inside using a coat hanger. I took a major bump on the head while seated on the lower bunk when the upper bunk fell as my husband climbed onto it, so you might be sure it's secure if that is the configuration in your sleeping compartment.

Romania, Hungary and Turkey are all worth the minor inconveniences!
Have a great trip, Saige

Thanks saige. It sounds as if you two were in a 2-berth compartment, not a multi-bunk couchette. Right? How was schedule performance? I've heard it's often not so hot.

Yes, a 2 berth. Sorry, too much other travel has occurred in the interim so I honestly don't recall the schedule performance. I just remember it being a long trip. Hope you'll post again if you have other questions as you plan your trip. We really enjoyed the month we spent in Romania and our time in Hungary and Turkey.

The Budapest-Bucharest 'Ister' sleeper train is reportedly usuaully on time into Bucharest, or only a few minutes late. Fantastic scenery, almost Alpine, as she descends through the Carpathian moumntains out of Transylvania, between Brasov and Ploesti.

The Bucharest-Istanbul 'Bosfor', due in Istabul at 07:50, is usually/typically an hour late, which is no big deal. But it's been known to be 3 or 4 hours late, so don't plan any tight connections.

Fab scenery at low speed as the Bosfor wanders through lush green river valleys all afternoon in Bulgaria.

Note that work may start in March 2012 on the track within Turkey, and there may be some disruption or bus replacement on the Turkish bit. But no firm details yet.

In the westbound direction, expect the 'Bosfor' to be 2 or 3 hours late into Bucharest. A same-day 30 minute connection with the Ister in Bucharest is simply not possible! However, once you're on it, the Ister will usually be on time into Budapest or only a few minutes late, from what I can gather.

Oh, and ALWAYS travel in the safe and comfortable sleeping-car. NEVER in a seat, it's the train equivalent of sleeping in a shop doorway.

A bed in a 2-bed sleeper only requires a 2nd class ticket plus 30 euros or so supplement, a bunk in a far more basic 6-berth couchette compartment is a 2nd class ticket plus 10-15 euros supplement, so the extra cost for big step up to sleeping-car comfort is a drop in the ocean really.

There's a restaurant car Budapest-Bucharest on the Ister, but nothing on the Bosfor, so pile your compartment high with a picnic and wine or beer bought from near the station.

That really sounds like a fabulous experience.