As part of my preliminary reading for our trip to the Balkans, I re-read Agatha Christie's Murder on the Orient Express. Poirot's journey actually began in Aleppo (in Syria), with a break to cross the Bosphorus, but it seems that since 2008 it's no longer possible to travel from there to Istanbul by train (http://www.seat61.com/Syria.htm#Istanbul%20-%20Aleppo%20by%20daily%20train%20&%20bus%20via%20Adana).
The hotel at which Poirot had dinner and had intended to stay at in Istanbul is named in the book as the Tokatlian, but presumably this is a reference to the Pera Palace Hotel which was built in 1892 for the purpose of hosting the passengers of the Orient Express. It receives only mediocre reviews these days!
However, Wikpedia states that the snow storm was based on an incident in February 1929, when an Orient Express train was trapped by a blizzard and was marooned for six days. This was near Cherkeskoy, in Turkey. The Wikipedia entry for this town states "The land here is flat, watered by the River Çorlu and good soil for farming", which would make it very similar to the area near Vinkovci. Hence Agatha Christie seems to have all the bases covered!
We've actually been on the line through Vinkovci twice. Once was years ago when we travelled from Paris to Belgrade on the Simplon Express ("Express" in name only, and no "Orient" because it only went as far as Belgrade) and the other time was not so many years back when we travelled from Belgrade to Zagreb (on a train that didn't even aspire to be an "express"). However, at the time we weren't aware that we were passing a place of literary significance.
I also understand that one of the James Bond stories (From Russia with Love) had some action on this line, but it's so long since I've seen that that I can't recall the scene.
It's a bit of an indictment that the rail trip from Belgrade to Vinkovci today takes almost 4 hours, whereas Agatha Christie had the Orient Express scheduled to do it in about 2 hours 43 minutes. I can certainly vouch for the fact that, presumably due to the condition of the track, the first couple of hours out of Belgrade are nowadays at an extremely slow pace. Today's timing may also factor in a delay at the border crossing from Serbia into Croatia, which was not an issue in the 1930s - but surely this can't explain all the extra time, given that the distance (according to Google maps) is 171 kms (this is by road, and seems to be a slightly less direct route than the train line).
However, there's been a slight improvement in rail travel times from Istanbul to Belgrade. Agatha Christie had this taking just under 24 hours. These days it takes just under 22 hours. Nevertheless, I doubt if it would be as comfortable these days, so on our forthcoming trip when we do this leg (in the other direction), we're flying.