What does the train ticket stubs represent in the book Catcher in the Rye?

The train ticket stubs in "Catcher in the Rye" symbolize Holden's desire to escape from reality and avoid adult responsibilities. They represent his longing for freedom and his fear of growing up. The train ticket stubs also serve as a recurring motif throughout the novel, reflecting Holden's restless and unsettled nature as he tries to find his place in the world.