Kawasaki Heavy Industries & Nippon Sharyo C751B

The front of the train sports a more slanted and streamlined look, with the run number display in Orange LED Display. The C751B train is the first train to have the updated SMRT livery that ran between 1999 and 2014.

These trains were fitted with Mobitec MobiLED electronic destination displays for train run numbers. The C751B was also the first MRT train type to feature anti-climbers, which help prevent overriding of the train cab in the event of a collision that could cause a catastrophic failure. They also feature rubber guards to prevent people from falling between cars: this feature was also used on the C151A.

All cars have been retrofitted with 6 LCD displays per car, and all except trainset 347/348 which features VPIS (Visual Passenger Information System) displays from July 2001 to September 2009. These used to show rail travel information, commercials and movie trailers. The C751B is also the first train to have wheelchair space, with the retrofitting of the elevators in the MRT stations began in 2000. The interior design was also improved; the seats were now 48 cm wide - about 5 cm wider than on previous train types.

The LCD screens were deactivated since July 2007 and LED displays was not used since January 2008 with the change of voice announcer. All VPIS were removed to make way for the STARIS by 2010. In 2013, support bars are added to the seats with hand grips, and the middle handrails with hand grips are configured to join across nearly one carriage, as such all triplicates stanchion poles are replaced by regular single grabpoles.

The colour layout on these trains are also different from their earlier counterparts. Cars 1 and 6 use a sort of pinkish-purple color on the seats, while cars 2 and 5 use a different shade of blue, and the middle cars using a bluish-green. All door panels and walls are white, which is a standard appearance of all SMRT trains.

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  Builder's plate of a Nippon Sharyo-built C751B train

The C751B is the second commuter type Electric Multiple Unit (EMU) after the Sanyo 5030 series to feature electric systems fully manufactured by Fuji Electric. Propulsion is controlled by VVVF Inverter with 2-level IGBT semiconductor controller, rated at 415 kVA. Each inverter unit controls two motors on one bogie (1C2M), and one motor car features two of such units. Motors are three-phrase AC induction type, model MLR109, with a maximum output of 140 kW.

The C751B uses the monolink axlebox type bolsterless air spring bogie. There are no major technical difference between a trailer and motor car bogie other than additional electrical components for the latter.

A break from tradition, the C751B features auxiliary inverters for its electrical systems on all six cars of the train. Previously, auxiliary inverters are mounted only on motor cars. The VVVF Inverter is controlled by IGBT semiconductors and rated at 80 kVA. A battery charger is built with the inverter and provides 16 kW output.

On 13 April 2002, a fault was detected in a C751B train and it was subsequently withdrawn to Changi Depot for investigations. As the train was under warranty, the engineers from the manufacturers of the train and gearbox were flown in on 21 April. They subsequently detected metal fragments in the gearboxes, and those of another 20 trains. On 23 April 2002, SMRT immediately withdrew all 21 C751B trains and suspended the Boon Lay – Changi Airport train through service, replacing it with the Tanah Merah – Changi Airport shuttle service.[6] Train frequencies were also adjusted until 6 May 2002, when 8 trains returned to service. Service resumed on 16 May 2002, with 7 more trains back on service.[7] By end of May 2002, all C751B trains had been returned to service.[8]

On 17 August 2011, a security breach occurred at Bishan Depot in which C751B set 311/312 was vandalised by 2 Americans named Jim Harper and Danielle Bremner (under the pseudonym Utah and Ether).[9] The graffiti was noticed only after the train had been in service for several hours. SMRT was eventually fined $200,000 by the Land Transport Authority.