The Kastner train consisted of 35 cattle wagons that left Budapest on 30 June 1944, during the German occupation of Hungary, carrying over 1,600 Jews temporarily to Bergen-Belsen and safety in Switzerland after large ransom paid by Swiss Orthodox Jew Yitzchak Sternbuch, Recha Sternbuch's husband. The train was named after Rudolf Kastner (aka Kasztner), a Hungarian-Jewish lawyer and journalist, who was a founding member of the Budapest Aid and Rescue Committee, a group that smuggled Jews out of occupied Europe during the Holocaust. Kastner negotiated with Adolf Eichmann, the German SS officer in charge of deporting Hungary's Jews to Auschwitz in German-occupied Poland, to allow over 1,600 Jews to escape in exchange for gold, diamonds, and cash.
The train was organized during the deportations to Auschwitz in May–July 1944 of 437,000 Hungarian Jews, three-quarters of whom were sent to the gas chambers. Its passengers were chosen from a wide range of social classes, and included around 273 children, many of them orphaned. The wealthiest 150 passengers paid $1,500 (equivalent to $22,000 in 2020) each to cover their own and the others' escape. After a journey of several weeks, including a diversion to the Bergen-Belsen concentration camp in Germany, 1,670 surviving passengers reached Switzerland in August and December 1944.
Kastner emigrated to Israel in 1947. He was a spokesman for the Minister of Trade and Industry when his negotiations with Eichmann became the subject of controversy. Kastner had been told in April or May 1944 of the mass murder that was taking place inside Auschwitz. Allegations spread after the war that he had done nothing to warn the wider community, but had focused instead on trying to save a smaller number. The inclusion on the train of his family, as well as 388 people from the ghetto in his home town of Kolozsvár, reinforced the view of his critics that his actions had been self-serving.
The allegations culminated in Kastner being accused in a newsletter of having been a Nazi collaborator. The government sued for libel on his behalf, and the defendant's lawyer turned the trial into an indictment of the Mapai (Labour) leadership and its alleged failure to help Europe's Jews. The judge found against the government, ruling that Kastner had "sold his soul to the devil" by negotiating with Eichmann and selecting some Jews to be saved, while failing to alert others. Kastner was assassinated in Tel Aviv in March 1957. Nine months later, the Supreme Court of Israel overturned most of the lower court's ruling, stating in a 4–1 decision that the judge had "erred seriously".