Sha Tin to Central Link

The Sha Tin to Central Link (abbreviated SCL; Chinese: 沙中線; Cantonese Yale: sā jūng sin) was an expansion project owned by the Kowloon-Canton Railway Corporation and operated by the MTR public transport network in Hong Kong. It was divided into two sections and expanded the network’s heavy rail lines.

The first section, named "Tuen Ma line (Phase 1)”, runs from Tai Wai station in the New Territories to Hung Hom station in Kowloon. The Tai Wai–Hung Hom segment connected the Ma On Shan line and West Rail line, forming the new Tuen Ma line. Operation of the Tai Wai to Kai Tak section began on 14 February 2020. The opening of the section from Kai Tak to Hung Hom was delayed and opened on 27 June 2021.

In anticipation of the Tuen Ma line, the existing Kwun Tong line was extended from its previous terminus at Yau Ma Tei to Whampoa station. This extension includes the new Ho Man Tin station to provide interchange with the Tuen Ma line. The Kwun Tong line extension was opened on 23 October 2016. While it was done in conjunction with the Sha Tin to Central Link, it is not considered a direct component of the project.

The second section (Phase 2) extended the East Rail line from Hung Hom in Kowloon to Admiralty on Hong Kong Island via a newly constructed station at Exhibition Centre. It opened on 15 May 2022.

The proposed route of the Sha Tin to Central Link roughly follows the scheme of the original East Kowloon line, which was proposed in the late 1960s but was not constructed. The Shatin to Central Link was included as one of the Priority Railway Schemes in the Hong Kong government's Railway Development Strategy 2000.

On 25 June 2002, the government announced that the Kowloon-Canton Railway Corporation (KCRC) had won its bid against the MTR Corporation (MTRC) to build and operate the Shatin to Central Link. The route was originally planned to go from Tai Wai station to Central West station (proposed to be located under the Mid-Levels), as an extension of the then-under-construction KCR Ma On Shan Rail (now the Ma On Shan line).

The KCRC announced modifications to the proposal in 2005, with the East Kowloon portion of the line joining KCR Ma On Shan Rail at Tai Wai and KCR West Rail (now the West Rail line) at Hung Hom, with the cross-harbour portion joining KCR East Rail (now the East Rail line) at Hung Hom. Mong Kok Station (now Mong Kok East) would have been relocated, joining a new tunnel to a deeper Hung Hom station platform connecting to the cross-harbour section. Additionally, stations at Tsz Wan Shan and Whampoa Garden were removed from the proposal; the areas would instead have been served by people movers (APMs) from other stations. However, the KCRC's proposal had not yet been finalised.

At the same time, the MTRC submitted a new proposal to the government. According to the proposal, the Kwun Tong line would be extended from Yau Ma Tei station to Whampoa station (as the KCRC had decided to omit Whampoa Garden station from its proposal), and the route of the SCL would follow the KCRC's original proposal instead of the 2005 modified proposal. An underground train depot would have been built beneath the passenger terminal of the former Kai Tak International Airport, adjacent to Prince Edward Road East in Kowloon City; however, under the Kai Tak redevelopment plan released by the government in October 2006, the depot would have to be constructed somewhere else.