and Kowloon City districts (the phase 1 East West Corridor), and extending East Rail line to Hong Kong Island's central business district (phase 2 North South Corridor). After the 2007 network merger, operations of all transport services (East Rail, West Rail, Ma On Shan Rail, Light Rail, feeder buses and Guangzhou–Kowloon through train) of the KCRC have been leased to the MTRC for 50 years. The MTRC also rebranded the three commuter railways to bear the suffix "line" (East Rail line, West Rail line and Ma On Shan line) like their own railways. Subsequently, the approved SCL schemes fall into the hands of the MTRC. The construction of East West Corridor, which largely followed an alignment proposed by the MTRC in the 1970s as the East Kowloon line and later shelved, began in August 2016. At the time, it was unclear how MTRC would name the new lines or whether they would retain the project codenames "East West Corridor" and "North South Corridor"; the word "corridor" would set a precedent in the naming convention of MTR lines. Speculation of a "East West Line" arose when a photograph of an info plate printed with "EWL" (東西綫) at Ho Man Tin station while it was under construction surfaced. The plate was removed before the opening of the station that year as part of the Kwun Tong line extension to Whampoa. MTRC eventually announced on 25 May 2018 that the finalised name was the Tuen Ma line. Construction defect and delay The Tuen Ma line was planned to be fully operational in 2019, but after concrete structures of the newly built platforms at Hung Hom station failed a safety inspection which occurred between December 2018 and January 2019, its full opening was postponed by about 2 years. The head contractor of the SCL construction, Leighton Asia, subsidiary of the CIMIC Group, was accused of covering up the defect of the construction until a whistleblower from a subcontractor leaked photo evidence to the local press. This led to more thorough investigations, hearings and inspections behind the set concrete for assessing if it would require demolition and rebuilding the structure from scratch. The Hong Kong government also expressed disappointment in the MTRC executives for their incompetent supervision. Michael Tien, former KCRC chairman, suggested that it was technically feasible to have the Ma On Shan line be initially extended from Tai Wai to Diamond Hill station