Head Crusher has the appearance of a professional wrestler and is a member of the Atchison Clan of the Rail Nomads. He sits at a table in the SE (lower right) corner of Scott's Bar, which is located on the south end of Quartz near the Graveyard.
If you visit the Brakeman at the Rail Nomads Camp and agree to do him a favor, he'll ask you to deliver a Visa card to Head Crusher. To deliver the visa card, sit at the table and use the visa card on yourself. Head Crusher will then tell you to visit the Atchison's tent and use the password "CATERPILLAR".
After completing the quest for the Brakeman, you can ask Head Crusher about things. However, for most things, he just says, "I sure love to chat, but that topic bores me," he says, and drinks his cloudy drink.