Alstom Metropolis C830C
The C830C runs without a driver, using Communications-based train control (CBTC), which does not require "fixed-block track circuits" to find where the train is on the track. Instead, they use "continuous two-way digital communication" between each controlled train and a control center, which may control an area of a railroad line, a complete line, or a group of lines. It has been found that CBTC systems reduce costs for running the system and allow the system to be controlled more easily.