C801+C801 or C801A+C801A. Occasionally units are mixed for reasons such as rescue operations or testing. Train control The line is equipped with Bombardier's CITYFLO 550 fixed block signalling system for automatic train control (ATC) under automatic train operation (ATO) GoA 4 (UTO). The subsystems consist of Automatic train protection (ATP) to govern train speed, Automatic Train Supervision (ATS) to track and schedule trains, and a computer-based interlocking (CBI) system that prevents incorrect signal and track points settings. When the Innovia APM 300R C801B enters service, the line will be upgraded to use Bombardier's CITYFLO 650 moving block communications-based train control (CBTC) signalling system. References External links Bukit Panjang LRT line 1999 establishments in Singapore Bukit Panjang Choa Chu Kang Innovia people movers Light Rail Transit (Singapore) lines Railway lines opened in 1999 Automated guideway transit