Industrial Ethernet in Intelligent Transportation System

IP-based Railway Control System

Speed, reliability, and safety are important factors for the efficient and economic operation of railway systems. To achieve this goal, modern railway system builders have found that automation technology can be used to lower the labor costs and enhance the real-time determinism of daily operations. However, railway transportation systems consist of many complex sub-systems together forming a distributed architecture which requires centralized control and monitoring. Because of the complexity involved, an open, reliable IP-based industrial Ethernet network that can connect to and communicate with all of the railway systems or multiple services is required to ensure intelligent management and easy integration.

System Description

The railway system contains many subsystems, including a Control and Dispatching System (Signaling System), Environment Monitoring System, Video Networking Surveillance System, Passenger Information System, Passenger Entertainment System, and Electric Power Supply System. These subsystems, which handle key aspects of railway operation, are generally distributed at remote locations, such as the different railway stations making up the rail line.

A layered network is often used to integrate all of these systems into one complete railway system.

	The device-level control network is a fieldbus network that uses gateways to communicate with the Ethernet network. All of the information transmitted from the field is forwarded to the upper layer network via the Ethernet network.
	The station-wide control network connects the main subsystems of each railway station with the Ethernet network. The station-wide networks are then integrated via the backbone network to transmit the operation information between stations.
	The backbone network collects and transmits all of the operation information from each station to the Central Control Room. In this way, the Central Control Room will have sufficient information for further control and analysis.

The device level network collects all of the operation information from devices such as PLCs, DCS systems, field I/O devices, and also SCADA. All of this information is communicated by the gateways or device servers and then sent to the Ethernet network. The backbone uses a high-bandwidth Gigabit Ethernet network, which provides enough bandwidth to handle high quality video surveillance and real-time emergency intercom systems. In addition, advanced wireless Ethernet roaming technology can be used to establish non-stop, two-way communication between the ground and trains. The three network layers connect all of the stations together, and integrate all of the information that is required to keep the system operating smoothly. The end result is a railway control system that is fast enough to respond in real-time, and that runs more efficiently.

Application Requirements

Railway transportation systems use mission-critical devices to provide on-time service. For this reason, networks that connect to all of the subsystems must meet or exceed high standards of vibration resistance, industrial ruggedness, network redundancy, and electromagnetic compatibility. A network used as part of a railway transportation system should satisfy the following requirements:

	Rugged IP-based On-Board Network: With an anti-vibration design and robust EMC capability for on-board operation, an IP-based train communication network ensures highest reliability. Specifically, real-time information updates and transmissions between trains and stations are attainable with industrial wireless Ethernet with advanced roaming technology.

	Wayside Long-haul Transmission: Railway systems consist of many stations, some of which could be separated by hundreds of kilometers. A network used to integrate operation information from that many stations must be capable of transmitting data over long distances.

	Centralized Railway System Monitoring: Railway control centers must process massive amounts of information from various subsystems. The networking devices must provide a high port density and flexible interface options. In addition, rack mount installations are needed to optimize space usage.

	Security Surveillance System: Ensuring passenger safety on platforms is of the utmost importance. PoE-compliant video surveillance systems, wireless access points, and emergency phones are an essential part of any real-time monitoring system.

	Reliable Station Network: A reliable and highly available network is needed to provide real-time information to both passengers and the railway control center. Such networks usually include a transport information system, automatic fare collection, intrusion detection in restricted areas, and IP video surveillance for security surveillance.

Moxa's Industrial Networking Solutions

The stability and reliability of network communication is at the core of constructing an intelligent railway transportation system. Moxa provides industrial device networking solutions to control and manage data from various sites. Moxa offers the following solutions that match the requirements of railway networks:

	EN50155/50121-3-2/50121-4 and e-mark Certified Moxa's industrial Ethernet switches, wireless Ethernet products and IP video solutions provide M12 anti-vibration interfaces for on-board train applications, and comply with strict rolling stock and wayside standards.

	Rugged and Fanless Design Moxa's industrial Ethernet switches are designed to withstand harsh environments. The switches feature a wide operating temperature range from -40 to 75˚C, power input options for use in different countries, and a full selection of high density, modular and Gigabit port DIN-Rail or rackmount Ethernet switches for use with a backbone infrastructure.

	Industrial Outdoor/Indoor Wireless Communication Moxa's Turbo Roaming™ technology, which enables seamless connections to wireless networks, provides ready access to an IEEE 802.11a/b/g wireless LAN. The wireless solutions feature IP67-rated housing, wide operating temperatures, and redundant power options.

	Industrial-grade IP Video Surveillance Moxa IP cameras' compact size and PoE (Power over Ethernet) interface was developed to save installation space and reduce the cost of power line deployment. In addition, Moxa's EN50155 IP camera is ideal for rolling stock applications.

	Expertise in Computing and Communications Moxa's ready-to-run embedded computers come with strong EMC and a fanless design to facilitate front-end communication, and provide a reliable and flexible solution for railway applications. Moxa's ioLogik Active Ethernet I/O offer proactive, condition-based reporting and the control of I/O devices used for PC-based data acquisition and control.

	Integration of Legacy Devices Into an Ethernet Network Moxa's NPort serial device servers offer a fast and economical way to connect legacy devices to Ethernet LANs.