This document discusses the implementation of a metro rail system using programmable logic controllers (PLCs) and supervisory control and data acquisition (SCADA). It describes how PLCs are used for automation and control functions, while SCADA is used for high-level supervision, data collection, and presentation. The document outlines the components, functions, and block diagram of a metro rail system that uses PLCs to interface with sensors and machinery, while SCADA is used for monitoring train locations to help avoid accidents and collisions.