The exteriors of refurbished trains resemble those of the C751B rolling stock.
The interior fittings were replaced with white walls and new seats and installed further back to allow more standing space.
Original: Two-phase DC shunt-wound motor (Mitsubishi Electric) 145 k W (194 hp) 375 V 430 A 2050 rpm (1 hour rating) Upgraded: Permanent Magnet Synchronous Motor (Toshiba, 025/026, 055/056, 065/066, 095/096, 109/110 and 131/132 only)Current: Westinghouse Brake and Signal Company Ltd fixed block ATC with subsystems of ATO GOA 2 (STO), ATP, ATS Thales Sel Trac® Moving Block CBTC ATC with subsystems of ATO GOA 3 (DTO), ATP, Net Trac ATS, CBI The Kawasaki Heavy Industries C151, sometimes abbreviated to C151 or KHI C151 is the first generation electric multiple unit rolling stock in operation on the North South and East West Lines of Singapore's Mass Rapid Transit (MRT) system.
These are the oldest trains built for the system; they were introduced in 1987 and are still in operation.
In November 2006 the doors of three cars (carriage number 3006, 10) were installed with a dynamic, in-train system displaying station information for testing; these are similar to ones used by Hong Kong's MTR.
Two years later, four units of vacuum fluorescent displays (VFD) were mounted on the ceiling.
However, in August 2016, LTA has placed this refurbishment programme on hold after acquisition of SMRT rail assets in August 2016 due to the concerns and issues with older trains.
LTA has evaluated on the decision to replace older trains with newer ones, despite the frames of the older trains being sturdy for decades.
The colour of seats in the driving trailer was changed from orange to red.
The wheelchair space was made available on the end of two mid-train cars, nearest to the lifts in above-ground stations.
The first trainset to receive this upgrade, which included a replacement traction system, entered service in July 2015.
In spite of SMRT having already purchased the replacement traction system, plans were put on hold when Land Transport Authority (LTA) acquired all of SMRT rail assets in August 2016 under the New Rail Financing Framework.
The trains were fitted with Stone Platt air-conditioning, Duwag bogies, Sig gangways, Scharfenberg couplers and Westinghouse brakes.