The Rotem EMU (also known as K-Train/K-Stock) is an electric multiple unit that operates on the MTR rapid transit railway system in Hong Kong. They were jointly built by a consortium consisting of Mitsubishi Heavy Industries of Japan and Hyundai Rotem of South Korea and come in two variants: TKE-C651 was delivered for the Tseung Kwan O line (used on the Kwun Tong line until 2009), and TKE-C6522-04E delivered in 2006 to 2007 for the Tung Chung line. In 2003 and 2004, the urban line trains ran on the Tsuen Wan line, Island line and Tseung Kwan O line.