沙田至中環綫
With the construction of the Sha Tin to Central Link, which cannot accommodate trains of greater than nine cars, the MTR decided in December 2012 to phase out all of the aging Metro-Cammell trains from 2020 and replace them with 37 sets of 9-car R-Stock trains built by Hyundai Rotem of South Korea. The first new train arrived in Hong Kong in September 2015 and entered service in February 2021. They will fully replace the older fleet in time for the opening of the Hung Hom to Admiralty section of the Sha Tin to Central Link.