What does subway bus mean?

The English letters mean environment and equipment monitoring system.

The purpose of the subway BAS system is to automatically monitor and manage station electromechanical equipment, provide a comfortable environment for passengers and operating personnel, save energy, and reduce operating costs.

The subway BAS system is an automated control system that combines computer and network technology with electromechanical equipment automation control principles, and is based on specialized subway environment ventilation, air conditioning, disaster prevention and other theories. It uses a distributed microcomputer monitoring system to monitor Comprehensive operation management and control of electromechanical equipment such as air conditioning and ventilation, water supply and drainage, lighting, elevators, escalators, and guide signs in subway stations and section tunnels.