Queensland Rail 2800 Class locomotives on a line near Mt Isa, about 960kms (596miles) northwest of Brisbane in this undated handout picture. Global miner BHP Billiton has offered to buy the Australian state of Queensland's coal freight business, The Australian said on December 16, 2009. REUTERS/Queensland Rail/Handout (AUSTRALIA - Tags: ENERGY BUSINESS) NO SALES. NO ARCHIVES. FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS