A $20 billion proposal to overhaul London's Tube by partially privatizing it was approved on Thursday. The proposal, which aims to sell off parts of the underground railway to the private sector, received the green light from the Board of London Regional Transport, the body that oversees the subway. Under the plan, Metronet and Tube Lines Group would take over responsibility for repairing the subway. The companies would be committed under contract to deliver specific improvements or be penalized, said the Associated Press. The operator of the subway, London Underground, will remain publicly owned. Major opposition to the partial privatization plan remains. The Health and Safety Executive can still veto the government's plans if he deems safety standards are not adequate.