How do infant day care centers put kids to sleep?

I don't know about day care centers at large but the centre where my kid was going, the care takers used to pat them to sleep. They had little cots on which they would pat them to sleep. Initially when my kid took time to adjust, caretaker would hold him in her arms and would walk to and fro the room till the time he would go to sleep. The caretakers in such centres are trained professionals and they know how to soothe babies.