On 3 September 2004, Hyundai Rotem, Mitsui, RM Transit Technology and dU LexBuild received an order to refurbish all 396 carriages, costing S$142.7 million in total. The works included the refurbishment of interior fixtures, the addition of wheelchair spaces, the upgrading of onboard communications equipment, enhancement of the public announcement system, and general improvement of the cars' appearance. SMRT Corporation said the reasons for refurbishment were wear and damage of important components over the past two decades and water leaks from the air-conditioning system on some trains. The company chose this option instead of buying new rolling stock, which would have cost S$792 million. The first refurbished train began revenue service on 5 November 2006, and all remaining trainsets had been refurbished by the end of 2008.