SMRT C651 Mid-life Upgrading Project

The C651 Mid-life Upgrading Project was a cancelled train refurbishment project undertaken by SMRT on nineteen Siemens C651 trains.

The nineteen Siemens C651 trains were manufactured between 1993-1994 by Siemens AG in Vienna, Austria. They entered service in 1995 on the North South Line (NSL) and East West Line (EWL), making them the second generation of rolling stock on these lines.

As their 30-year design lifespan was approaching, Singapore Rail Engineering (SRE), a subsidiary of SMRT Corporation, was tasked with the mid-life upgrading of these trains. The project began in 2015, but was abruptly terminated in 2018, despite the completion of up to three refurbished trainsets (217/218, 225/226 & 227/228) and some on-track running carried out during engineering hours.

Refurbished trainsets were scrapped starting from 2021.

Article Layout

  • Background to SRE
  • Background & timeline of C651 MLU
    • Project Launch
    • Scope of refurbishment works
    • Project Termination
    • Scrapping of refurbished trains

This article was originally titled: SMRT stops Mid-life Upgrading of C651 Trains.

Background – SRE

Singapore Rail Engineering (SRE) was incorporated in 2014 under SMRT Corporation, with the intention of growing an indigenous rail engineering capability contributing directly to rail reliability in Singapore. It develops and invests in core engineering expertise, and trains skilled personnel to provide a complete set of engineering services to support and maintain the SMRT metro network, while also making headway in opening up overseas engineering services markets.

The SMRT subsidiary mainly targets rail MRO (Maintenance, Repair, and Overhaul) activities arising from the maintenance cycle of rolling stock, including the midlife upgrading and/or refurbishment of trains that have been in operation for 15 years or more. It also formed joint ventures with Toshiba and Faiveley Transport.

At the time of the C651 refurbishment project’s termination in 2018, SRE was refocused to deepening its capabilities in subway operation and maintenance engineering, in line with new requirements set out by the New Rail Financing Framework.

Background & Timeline – C651 MLU

Project Launch
Siemens C651
Siemens C651

Plans to refurbish the C651 train were first mentioned in a blog on SMRT’s website in December 2015. As part of the Siemens C651 Mid-life Upgrading Project (or C651 MLU), SMRT and SRE were finalising the proposed improvements for the train design, and intended to refurbish and test a prototype train in 2016. The project was initially slated for completion in 2018.

As SRE was a newly-formed SMRT subsidiary, the C651 MLU was essentially carried out in-house. In contrast, mid-life refurbishment of the C151 trains carried out in 2006-2008 was outsourced to Hyundai Rotem.

In the August 2016 issue of Your Journey Matters by SMRT, it was mentioned that SRE had completed the upgrading of two prototype trains and was committed to proceeding with the upgrading works for the remaining C651 trains.

On 16 November 2016, SMRT delivered a progress update on the C651 MLU project during a site visit to Bishan Depot as part of an annual meeting of CoMET (Community of Metros), where the interior of the refurbished C651 train was showcased for the first time.

Scope of refurbishment works

The MLU programme would entail the replacement of almost all components of the train, such as the propulsion system, air-conditioning system, auxiliary power system, train management system, as well as the interior and exterior liveries, and door and gangways.

The propulsion system upgrade included the installation of IGBT-VVVF Permanent magnet synchronous motors (PMSM) from Toshiba, replacing the original GTO-VVVF traction control supplied by Siemens. This was expected to reduce power consumption by 30% and reduce operating noise by up to 12 dB. SRE and Toshiba had previously collaborated on integrating its PMSM motors on six C151 trains, and in September 2014, the two companies founded Railise Pte Ltd, a 50:50 joint venture that offered Toshiba PMSM upgrades to rolling stock refurbishment projects outside of Japan.

Two trainsets were refurbished first: 217/218 and 227/228. Extensive testing of these two prototype trains would be required prior to the commissioning and rollout of similar upgraded systems onto other C651 trains. A third refurbished train was later identified – trainset 225/226.

The following photos were released as part of the November 2016 event, showcasing the refurbished Train Car 2217 (Part of Train Set 217/218).

All-around aesthetics were enhanced: the trains received a new exterior coat of paint in the form of SMRT’s pixel livery, similar to that used on the C151B trains. On the interior; flooring, wall panelling, windows, handrails, and grab-poles were renewed for a cleaner and more spacious look. The upgraded train also featured two wheelchair bays per train car and an Active Route Map (STARiS 2.0) above each passenger door.

In July 2018, a Train Operations Review published by SMRT Trains mentioned that the first prototype is undergoing extensive testing, while the project completion year was revised to 2019 (having been delayed from 2018). That same month, on-track running was carried out during engineering hours and documented by local trainspotters.

Project Termination

The announcement of the project’s termination came on 16 September 2018, which was considerably late considering that trains were already undergoing extensive testing in preparation for passenger service the following year. The news was announced in a response to an inquiry by local Mandarin news publication Lianhe Zaobao and later also carried by The Straits Times.

Several reasons were cited by SMRT to the termination of the C651 MLU, including the transition to the New Rail Financing Framework (NRFF) in 2016 and recent changes in SMRT Corporation’s management structure. As part of the NRFF, which came into effect in October 2016 for the North South and East West lines, the LTA owns and makes decisions on building-up, replacement, and upgrading, while the Rail Operator (SMRT Trains) remains responsible for maintenance. Previously, before the NRFF, the Rail Operator owned, maintained, and made decisions on building-up, replacement, and upgrading, which was the basis for starting the C651 MLU project in the first place. From an operational point of view, SRE’s mid-life upgrading work was thus excluded from the NRFF equation despite progress having already been made on the C651 MLU project, since asset upgrading was now under the purview of LTA.

Online sources have also rumoured that the refurbished C651 train developed many faults whilst undergoing testing, raising concerns about the operational safety of the train. As SRE was a newly-formed SMRT subsidiary, the C651 MLU was essentially carried out in-house, representing a steep learning curve for the young company. In contrast, mid-life refurbishment of the C151 trains carried out in 2006-2008 was outsourced to Hyundai Rotem, a South Korean company with more than 25 years of rolling stock experience at the time.

The circumstances behind the termination of the C651 MLU project are yet to be completely made known (and probably never will be).

As a result, the focus of SRE was diverted to deepening its capabilities in subway operation and maintenance engineering, in line with the NRFF’s expectations for Rail Operators. According to news articles reporting on the matter, SMRT had also notified the Land Transport Authority of its intentions to stop the C651 MLU project.

Scrapping of refurbished trains

Main article: Decommissioning of C651 trains | Land Transport Guru

At the time of project termination, refurbishment works were conducted on three prototype trainsets (217/218, 225/226, 227/228), and testing works had not been fully completed. The abrupt termination meant that over two years of work had gone to waste, and no updates on the project would follow.

On 28 September 2020, brand-new Bombardier Movia CR151 trains were confirmed as the replacement for C651 trains, precluding any form of major refurbishment work on C651 trains. The base tender for 66 CR151 trains was awarded to Bombardier in July 2018 as direct replacements for first-generation C151 trains, and an additional 40 trains were announced in September 2020, as direct replacements for C651 and C751B trains.

The scrapping of these trainsets marked the end of the C651 mid-life upgrading efforts.

The scrapping of trains was observed as follows:

  • Trainset 227/228 – Scrapped in January 2021
  • Trainset 217/218 – Scrapped in April 2021
  • Trainset 225/226 – Set 225 scrapped in May 2021.

Trains were scrapped at Toyotron Pte Ltd, the same contractor that was awarded a contract to scrap 66 first-generation C151 trains.

More photos are on the dedicated article: Decommissioning of C651 trains.


C651 train – Unrefurbished
SMRT Facebook post


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9 thoughts on “SMRT C651 Mid-life Upgrading Project

  • 20 March 2021 at 12:23 AM

    2nd generation since 1994 C651 must should be refurbishment at early at 2014 to 2018 not 2016 to 2018 because money is expensive then so 2nd generation since 1994 C651 must should be refurbishment at early at 2014 to 2018

  • 18 January 2021 at 9:03 AM

    Sadly one of them got the scrap. A complete waste of money and resources. I mean what’s the point of refurbishing them and leaving to rust inside the depot instead of them into service

  • 9 June 2020 at 11:14 AM

    Does anyone knows what happened to the 2 completed trainsets? After the live testings during the engineering hours, they haven’t been seen ever since! The abruptly aborted refurbishment got taxpayers’ money wasted, especially when these European makes are costlier assets from the beginning….

  • 31 May 2020 at 2:23 PM

    I hope the refurbishment of the C651s will continue in the near future.

  • 1 November 2018 at 10:42 AM

    So they are gonna retire the C651 🙁

    • 18 May 2019 at 9:46 AM

      Hope tat in this case they will either add additional 19 cr151 trains or may add another new contract such as siemen inspiro to replace the overaging trains.


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