His hand on the dead-man throttle, the driver of the Serbian Rail diesel felt the thrill he always did on this particular stretch of railway, heading north from Belgrade and approaching Novi Sad.

This was the route of the famed Arlberg Orient Express, which ran from Greece through Belgrade and points north from the 1930s until the 1960s. Of course, he was not piloting a glistening Pacific 231 steam locomotive towing elegant mahogany-and-brass dining cars, suites and sleepers, where passengers floated upon vapours of luxury and anticipation. He commanded a battered old thing from America that tugged behind it a string of more or less dependable rolling stock packed snugly with mundane cargo.

But still he felt the thrill of history in every vista that the journey offered, especially as they approached the river, hisriver.

And yet he was ill at ease.

Among the wagons bound for Budapest, containing coal, scrap metal, consumer products and timber, there was one that worried him greatly. It was loaded with drums of MIC – methyl isocyanate – to be used in Hungary in the manufacture of rubber.