East Rail Line first opened in 1910. The lines was called KCR East Rail before the "MTR–KCR merger". The line has 14 station with the length of about 42 km. The new R-train entered service in 2021 and platform gates will be installed afterwards. The IKK-train are converted to 8-car sets to serve the Tuen Ma Line and the MLR train will be retired before the line extends to Admiralty in or after 2022.