The M-Train, along with the later C-Train and ex-KCR stock, has five sets of double-leaf sliding doors on both sides of each car. This is opposed to K-Stock and A-Stock which use plug doors. They are currently operating primarily on the Tsuen Wan line and Island line but are also operating on the Kwun Tong line and Tseung Kwan O line alongside newer rolling stock. Each car is 3200 mm width over body panel, floor to rail is 1100 mm high and roof to rail is 3910 mm high. The refurbishment process involved altering the fibreglass facade on the exterior ends to modernize their appearance, as well as the installation of the advanced digital voice announcement and passenger information systems. United Goninan was subsequently awarded a contract to maintain the MTR rolling stock. Such advances were not integrated into the M-Stock until late 2001. A service train has an acceleration of , service brake is regenerative blend with air brake at the rate of and emergency brake is air-brake at . The maximum speed for the M-Stock is 90 km/h, which is limited to 80 km/h during normal operation. Trains are also fitted for driverless operation, though they are not operated as such. Primary suspension is chevron springs, while the secondary suspension is air bags. Traction system is through GTO chopper control. Each car has 45 seats and capable of holding 268 standing passengers, with space for wheelchairs. Another refurbishment was planned that will update the trains' interior and exterior features to make them feel more modern; however, with their retirement and complete replacement impending, this is unlikely to happen before withdrawal of the stock.
When the Disneyland Resort line opened in 2005, some Second-hand M-Train units were refurbished and assigned to the line. The MTR designed a new driverless train and produced it by refitting existing M-Trains for the line which is designed with a Disney theme in mind. Statues of well-known Disney characters are included inside of the trains, such as Mickey Mouse and Donald Duck. Units A/C274, A/C281, A/C284, A/C289, A/C291 and B/C490 of M-Train have been assigned to the Disneyland Resort line and completely refurbished into new trains. There are major differences on the Disneyland Resort line trains compared to the main line trains.
For B/C490, a cab has been added to the B car.
The train cars have only 3 doors per side, for a total of 6 doors per car.
The trains use electric doors instead of air-powered doors.
Each car is wide over body panel, floor to rail is high and roof to rail is high. A service train has an acceleration of , service brake is regenerative blend with air brake at the rate of and emergency brake is air-brake at . The maximum speed for the M-Stock is, and are normally operated automatically without drivers. Primary suspension is chevron springs, while the secondary suspension is air bags. Traction system is through GTO chopper control.
Variants
M-Train is divided into 6 types of stock. They are the:
The traction system of M-Stock and T-Stock trains were changed to Chopper from Cam Shaft in 1992–1995, so they are called CM-Stock and CT-Stock now. All I-Stock trains belong to Island line, but all G-Stock, Q-Stock and H-Stock trains belong to Kwun Tong line, Tseung Kwan O line and Disneyland Resort line respectively. The configuration of a M-train in revenue service is A-C-D-C-B-D-C-A or A-C-C-A. There was once a type of trains with all motor A-C-C-B-C-B-C-A, but it was ungrouped into Disneyland Resort line trains. Units A/C274, A/C281, A/C284, A/C289, A/C291 and B/C490 have been assigned to the Disneyland Resort line and completely refurbished into new trains
Phases
Phase 1
The MTRC placed its first train order with Metro-Cammell in July 1976, initially ordering 140 railway carriages. The M-Stock trains were the first batch of trains ordered by MTR. They were delivered from 1979–1982, and had their traction systems changed to GTO Chopper from Cam Shaft in 1992–1995. They serve on the Kwun Tong line.
Phase 2A
The T-Stock trains were the second batch of trains ordered by MTR. They were delivered from 1982–1985 and also had their traction systems changed to GTO Chopper in 1992–1995. They serve on the Tsuen Wan line. Only A/C182 changed their traction systems earlier. It was changed from Cam Shaft to RCT Chopper in 1983, then in 1987 it was changed again to GTO Chopper.
Phase 2B
The I-Stock trains, the third batch of trains, were ordered by MTRC for the planned Island line in 1981. They were delivered from 1985–1986 and serve on the Island line. B/C459 used Cam Shaft till 1987. However, all the other trains used RCT Chopper, while B/C459's parts were from A/C182.
Phase 2C
The G-Stock trains were built for the Eastern Harbour Crossing extension of the Kwun Tong line, they were delivered from 1988–1989 and still serve on the Kwun Tong line. However, they moved to Tsuen Wan ;ine starting from December 2017. They were the last batch of MTR M-Trains to be made by Metro-Cammell before being acquired by GEC-Alsthom in 1989.
Phase 3
The MTRC signed a contract in March 1992 for 64 new rail cars with an option for an additional 24 carriages. These were delivered by Metro-Cammell as components, with final assembly carried out at the Kowloon Bay Depot. The H-Stock trains were delivered from 1994–1998 and some units were refurbished to serve on the Disneyland Resort line. 88 cars were built locally at Kowloon Bay depot.
Q-Stock
The first batch of Q-stock D-car units were ordered as part of Phase 2A T-Stock trains from 1984–1985, units D601-706 and D707-724; the second batch were ordered from 1985–1986; the third batch were ordered from 1988–1989, and the fourth and final batch were ordered from 1994–1998 as part of Phase 3. Each car is wide over body panel, floor to rail is high and roof to rail is high.
Surplus / retired cars
The surplus cars are B/C493 and D737. Some of the useful parts used on those trains have been removed in order to give them to other cars, so it may no longer be used. The retired / written off cars are B/C459 and D652. B/C459 was taken out of service in 2008 due to motor part issues from A/C254 and lack of Phase 2B parts, so B/C404 took over B/C459 on A/C227 - A/C170. Additionally, D652 was severely damaged in 2019 Central Station Crash, thus it was scrapped and replaced by D784. The original surplus cars were A/C115, A/C145, A/C273, B/C404 and D784.
Train configurations
Replacement
All 93 sets will be retired from service around 2021–2023. MTR had originally planned to replace 78 sets. However, in July 2015, MTR announced that CSR Qingdao Sifang had won an order to build 93 sets that is set to replace all M-Trains by 2023, on grounds that it was "better value for money". In addition, the current Westinghouse signalling system will be phased out in favour of a communications-based train control system, similar to that of the West Rail line and South Island line. In the meantime, 36 of the M-Trains have been equipped with CBTC equipment, supplied by Thales, for use on the Tsuen Wan Line as an interim measure while their replacement trains are being delivered.
