answer: #Person1# asks #Person2# to help with buying a train ticket for Philadelphia.
documents: #Person1#: Is there a train leaving for Philadelphia?
  #Person2#: Yeah. There's an express that leaves in twenty minutes.
  #Person1#: May I buy a ticket here at the station?
  #Person2#: Sure.
  #Person1#: Where?
  #Person2#: Go to window number eleven.
  #Person1#: Thanks.