MORE than 10 tonnes of rubbish have been left behind each day by passengers on the Guangzhou underground railway since it began operations on Tuesday. The subway's management company was forced to hire extra workers to help clean up the mess from 11pm to 8am daily, the New Express Daily reported yesterday. Rubbish was found in train compartments, along platforms and in ticket lobbies, maintenance manager Liang Xiangdong said. Chewing gum was stuck to seats. Guangzhou's Metro Line No 1 represents a triumph of engineering skill and endurance for the traffic-congested city. The railway, built at a cost of 12.7 billion yuan (HK$11.8 billion), extends over 18.5km and includes 16 stations, crossing some of the most heavily populated areas of the city.