In chapter 1, describe the conditions in the train (at the end of the chapter).

When Elie and the other Jews were taken out of the Ghetto, they were transferred to "cattle cars."  The Hungarian police crammed 80 people into each car.  There was a person assigned to each car to make sure no one escaped.  There were bars on the windows and the people were "sealed" inside with some bread and a few buckets of water.  (pg.22)

We read that there was not enough room for the people to lie down, and they had to take turns to sit down.  The air was limited and there was no way to get comfortable.