In Night, what does author Elie Wiesel say is left behind in the trains other than the Jewish people's last valuables? What does he mean by this?

In Night, upon arriving at Auschwitz, author Elie Wiesel says,

"The cherished objects we had brought with us thus far were left behind in the train, and with them, at last, our illusions" (Wiesel 27).

Before the train pulled into Auschwitz, the Jewish people from Sighet still had hope. There was talk about "resettlement camps," where the men would work, and conditions might be hard but tolerable. Some even thought wherever they were going might not be bad at all. They would be able to continue their lives much as they had before, and eventually they would be able to go back home to their village. These were the illusions about which Wiesel wrote. The Jews had no idea how bad things were about to become; but as they stepped off the train at Auschwitz, they could see the fires, they could smell flesh burning, they could feel the Nazis' truncheons hitting their bodies. They had no choice but to leave their illusions behind once the reality of Auschwitz struck them.