The East Rail line Metro Cammell EMU (also known as Mid-Life Refurbishment Train, Chinese: 港鐵中期翻新列車; or MLR Train) was a model of electric multiple unit built in 1980–1990 by Metro-Cammell for the original Kowloon–Canton Railway (now the East Rail line) in Hong Kong.

Sets E1-E45 and E46-E61 were delivered to KCRC in 2 batches in 1982–1983, when electrification was first completed between Hung Hom and Sha Tin in May 1982, and then to Tai Po Market station, and finally to Lo Wu on 16 August 1983.

In the early days of full electrification, these trains sometimes suffered from a temporary loss of electricity while passing University Station because of neutral sections (or dead zones), which was due to the lack of internal batteries.

Included in the refurbishment was changing the colours to teal and a touch of red, with a fire resistant floor, along with installation of emergency stairs for passengers to safely disembark to the trackside, and the installation of 22 in (559 mm) LCD screens mounted above windows, broadcasting looping daily TV news provided by Cable TV Hong Kong (Newsline Express) and advertisements.

On 25 November 1984, an East Rail Metro Cammell EMU train derailed between Sheung Shui and Lo Wu station.

However, the accident caused train services to be suspended for the rest of the day and the incident spurred a series of public outcries concerning railway safety.

On 17 September 2019, a 12-car Metro Cammell EMU train(E81/E21) servicing the East Rail line derailed while approaching Hung Hom station.

Following examination of the train, KCRC staff detected minor cracks in the welding of mounting brackets for some underframe components.

[4] This resulted in a decreased frequency (from 24 to 23 trains per hour) and lengthened trip time (increase by 90 seconds to 42.5 minutes).

The Environment, Transport and Works Bureau reprimanded the KCRC for not immediately notifying the Government when it found problems with its East Rail trains in 2005.

Secretary for the Bureau Dr Sarah Liao said she has ordered the KCRC to inspect all its trains, and did not rule out suspending services if there are safety doubts.

Dr Liao ordered the chairman to review the corporation's operations, including its management and overall system, and submit a report.

KCRC chairman Michael Tien accepted responsibility for the corporation's poor judgement in not sharing the information with the public in a timely matter.

[4] All 29 MLR sets had been gradually retired from service starting in 2021 (E92/E70 was scrapped in 2020) and, together with the newer SP1900 EMUs built by Kinki Sharyo, were replaced by brand-new Hyundai Rotem EMU trains ordered in December 2012.

[1] A 1:1 scale model of an in refurbished Metro Cammell EMU was once on display at the Hong Kong Railway Museum, built from components of carriage 272 of set E58.

Due to the extensive damage, coaches 234 and 235 were wrecked in the 1984 accident in a siding, and the only remaining historical train was E44 (144-244-444) and 445 (now preserved at Hung Hom Station).