# Siemens C651

The Siemens C651 was the second generation electric multiple unit rolling stock that operated on the North–South and East–West lines of Singapore's Mass Rapid Transit (MRT) system, manufactured by Siemens Mobility (SIE) and SGP Verkehrstechnik in Vienna, Austria under Contract 651. A total of 114 cars consisting of 19 trainsets were purchased in 1992 and were in service from May 1995 to September 2024.

## Design
### Initial design

The trains had a full white body and a thick red stripe in the middle. Similar to the Kawasaki Heavy Industries C151 trains, the Siemens C651 trains had no visual passenger information systems but had a built-in audio announcement system until STARiS was installed and activated around 2010.
Unlike the 66 first generation Kawasaki Heavy Industries C151 trainsets, the C651s were delivered with a scratch-resistant acrylic finish. This alleviated the difficulty of removing dirt trapped on the exterior surface, as opposed to the aluminium finish of the C151 trains that were delivered unpainted. The train run number at the front and rear of the train was delivered by a low-power consumption electronic green flip-dot display.
The C651 trains were originally delivered with a GTO-VVVF propulsion system that was supplied by Siemens.
Other original features included specifically designed air-conditioning vents that eliminate dripping from the cooling system to the train compartments, as well as an event recorder, which records important train functions, such as braking and emergency operations to assist troubleshooting in an event of a failure.
The C651 was also the basis for the Taipei Metro C321 and Taipei Metro C341 built from 1998 to 1999 and 2003 respectively for the Taipei Metro Bannan Line, as well as those used on Kaohsiung Metro.

## Operational history
### Tendering process

The design and supply of the C651 trains were tendered in December 1992 to complement the 66 first generation C151 trains with the opening of the Woodlands extension, at a cost of $259 million. These trains began revenue service from 2 May 1995, with the first train set delivered to the Mass Rapid Transit Corporation (MRTC) of Singapore on 20 September 1994.

### Experimental programmes

A number of experimental programmes had been run on the C651 cars.
In the 2000s, the third and fourth cars, coloured in green had all but eight seats, four at each end of the car, removed completely. In its place was standing room with upholstered cushion, in an attempt to provide a degree of comfort to passengers standing in that space. This design proved to be unpopular with the commuters, and it was eventually dropped. The original seats between the 1st and 2nd door and the 3rd and 4th door on these cars have been replaced. The remaining upholstered seats were reverted to original seats in May 2006. All C651 trains have had their seats on the middle part of carriage removed.
Some trainsets were reconfigured to have more standing space in the late 1990s as part of an experimental programme. In particular, the second and fifth cars (the blue cars) were reconfigured to have more standing room on both sides of a seat row, as 3 seats from some later cars.
More grab poles were also added to some cars. Regular grab poles in the centre of each car were replaced by grab poles that branch out into three in the centre, first in 2007, followed by triplicated hand grips and grab poles in 2014. Special non-slip floorings were also tested.
* Upholstered cushions, part of an experimental program. They have since been replaced by original seats.
* Modified flooring of some cars of C651 Set 237/238
* The interior of a Siemens C651 car. Modified grab poles and standing spaces, part of an experimental program, can be seen.

### Refurbishment and retirement

In 2015, refurbishment contracts for all 19 C651 train sets were awarded to Singapore Rail Engineering (SRE). When completed, these upgrades would have addressed components such as doors and brakes that have been the primary cause of delays owing to train faults. The changes planned included re-signalling, refurbishing the propulsion system, air-conditioning system, auxiliary power system, interior saloon with modifying handrails, replacement of the gangway connections and improving the exterior of the trains. Upgraded trains would also have had sensors that carry vital information on the train's state of health for improved operation and maintenance of the train set.
Refurbishment works began in January 2016, starting with EMU 217/218. The refurbished trains would also have included STARIS version 2.0, which consists of dynamic route map displays. The refurbishment of all 19 C651 trains was projected to be completed by 2019. However, in September 2018, SMRT announced that refurbishment works were abruptly terminated for the C651 mid-life upgrading project. At the time of project termination, refurbishment works were conducted on three prototype trainsets and testing works had not been fully completed.
In December 2019, Toyotron Pte Ltd was awarded the contract for disposal of old SMRT trains. On 6 September 2020, the first C651 train (set 203/204) was sent for scrap. This was followed by an announcement from LTA on 28 September 2020, that a second batch of 40 new Alstom Movia R151 trains to be delivered from 2025 onwards was ordered to replace all 19 C651 trainsets, together with the 21 C751B trainsets, on top of the initial order of 66 R151 trains replacing the 66 C151 trainsets. By May 2021, all refurbished C651 trains were scrapped without re-entering revenue service. In July 2024, it was revealed that parts from a decommissioned C651 trainset (set 215/216) such as train doors, seats and map displays are being preserved at the National Museum. On 30 September 2024, the last two C651 trains in revenue service (sets 201/202 and 207/208) made their final runs on the North–South Line and East–West Line Changi Airport Branch respectively; they were sent to Tuas Depot to await scrapping on 4 October 2024, ending its 29 years of service. The C651 fleet was officially retired on 27 November 2024, with carriages of the last remaining C651 train (set 237/238) scrapped or preserved between 27–30 November 2024. This was also the first ever rolling stock fleet in Singapore's MRT to be fully decommissioned.
These are the trains that are preserved:
| Trainset | Car number(s) | Notes | Rules |
| 229/230 | 3229, 1229, 1230, 3230 | Donated to Singapore Police Force for training purposes in August 2021. Strictly no unauthorised entry, photography and/or filming allowed. Deadly force may be used against trespassers. Cars 2229 and 2230 were sent for scrap in August 2021. | |
| 237/238 | 3237, 3238 | Currently stored in Tuas Depot, awaiting preservation. Cars 1237, 2237, 1238 and 2238 were sent for scrap in November 2024. | |
Incidents
C651 Door Dislodged
15 December 1997 (4:15pm) - A C651 trainset was undergoing modifications at Bishan Depot by Siemens before being deployed for the evening peak period. One of the doors was not properly reinstalled during the modification works, which resulted in the door getting dislodged while the train was approaching City Hall Station and at the same time smashing one of the platform screen doors. Siemens was held liable in this incident.
Ang Mo Kio Siding Derailment
13 April 1999 (10:00 am) – An off-service C651 (set 227/228) was on its way back to Bishan Depot after running during the morning peak period. It derailed between Yio Chu Kang and Ang Mo Kio stations. The derailment occurred because the station master had failed to reset the track alignment properly. Disruption to train services lasted about 7 hours.

## Train formation

The configuration of a C651 in revenue service is DT–M1–M2+M2–M1–DT.
Cars of C651 :
| Car Type | Driver Cab | Motor | Collector Shoe | Car Length | Car Length | Wheelchair Space |
| Car Type | Driver Cab | Motor | Collector Shoe | mm | ft in | Wheelchair Space |
| DT | ✓ | ✗ | ✓ | 23,650 | 77 ft 7.1 in | ✗ |
| M1 | ✗ | ✓ | ✓ | 22,800 | 74 ft 9.6 in | ✗ |
| M2 | ✗ | ✓ | ✓ | 22,800 | 74 ft 9.6 in | ✓ |
The car numbers of the trains range from x201 to x238, where x depends on the carriage type. Individual cars are assigned a 4 digit serial number. A complete six-car trainset consists of an identical twin set of one driving trailer (DT) and two motor (M) cars permanently coupled together. For example, set 201/202 consists of carriages 3201, 1201, 2201, 2202, 1202 and 3202.
* The first digit identifies the car number, where the first car has a 3, the second has a 1 & the third has a 2.
* The second digit is always a 2, part of the identification numbers
* The third digit and fourth digit are the train identification numbers. A full-length train of 6 cars has 2 different identification numbers. For example 201/202 (normal coupling) or 201/203 (cross-coupling).
** Siemens built sets 201 – 238.