id definition D Deadhead Locomotive or Caboose E Empty L Load O Operating Locomotive or Caboose W Revenue Empty AA Empty and Available at Pool AB Out Empty to Pick Up Cargo from the Shipper AC Loaded en route to port of loading or baseport AG Received at port of discharge or baseport AH Loaded en route to consignee AI Stripped and en route to pool from a consignee AJ Empty Positioning AK Out of Service AL Empty Non-hazardous Last Contained