In response, SMRT announced it was replacing important engineering components on all C151 trains by 2019. This included changing the existing Mitsubishi Electric propulsion system for the newer Insulated-gate bipolar transistor (IGBT) and Permanent Magnet Synchronous Motor (PMSM) propulsion system by Toshiba, technology currently used in the Tokyo Metro's 1000 series and 16000 series trains as well as the JR Kyushu 305 series and Hankyu 1000 series trains. Some Japan private railways also had their test trains using this technology, like one of the Keikyu's N1000. In July 2015, train sets 055/056 and 131/132 are trialed with the new propulsion system on the Changi Airport Extension. The trial was successful and by June 2017, only six trainsets, 025/026, 055/056, 065/066, 095/096, 109/110 and 131/132 had the new propulsion system. In tandem with the replacement of the signalling system on the East-West Line and North-South Line with the newer Thales SelTrac signalling system, new equipment are installed in the passenger compartment of the trailer cars.