When one sleeps with a girl from the HME he immediatly is on the train for life (thats why we refer to it as an express). The whoriest of the HME will be the caboose (for obvious reasons) and the leader of the group that is the conductor is basically the pimp who whores the other whores out. Do not be confused, the conductor is still a whore herself, but she instructs the others to target prey.
Bobby: hey i think i gotta go ge checked for aids...
John: why? did you sleep with anyone from the HME?
Bobby: i banged them all.
HME:I need a new shirt to go out toight, i guess i have to sleep with the manager of RAVE again.