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Ethernet defines new rail ‘network’ in Denmark03 May 2010Network enabled trains are able to integrate security, surveillance, passenger counting and infotainment technologies efficiently and reliably. We discover how Ethernet switches have achieved these goals for the Danish State rail operator, DSBEthernet switches are providing Danish State rail operator, DSB with Ethernet LAN backbones on its fleet of trains. They are used to configure virtual local area networks (VLANs) for various internal train systems, providing network connections for in-carriage IP-enabled security and surveillance equipment, infotainment systems, and passenger counting technology.
The switches used on this application are GarrettCom 6KQ units, which met DSB’s need for a compact, cost-effective ten-port Ethernet switch, with Gigabit bandwidth, all in a hardened package and EN50155 compliant for railway applications.
A 6KQ switch is mounted in each carriage and linked in a bus topology to provide an Ethernet backbone along the length of the train. The switches provide central points in each carriage into which the IP-enabled equipment can be readily connected. The backbone is also connected to a wireless local area network (WLAN) gateway, which handles the network traffic between the train and the outside world, the network packages being transmitted and received via an antenna installed on the roof of the carriage.
The 6KQ units are all powered from an auxiliary 110V dc system, serving each coach, and are fully managed using GarrettCom’s MNS-6K software. This simplifies the process of realising optimum network traffic for all subsystems.
Safety, security and efficiency
Train and network operators are increasingly looking to provide passengers with an improved journey experience, focusing on safety, security and efficiency. Much of this can be addressed with modern CCTV and video recording technology. CCTV cameras mounted in the carriages and linked to video recorders form an effective surveillance system that acts as a deterrent against crime and anti-social behaviour, including attacks, vandalism and graffiti damage.
CCTV cameras in the DSB carriages are linked to video recorders over Ethernet via the 6KQ switches. Log files of the recorded data are transmitted from the video surveillance system server to a central office via the WLAN, which also transmits the train’s position information in real time. At the same time, it provides passengers with a free Internet connection as part of the infotainment system.
In addition to the security and infotainment systems, DSB’s implementation of passenger counting technology is of particular interest. Ethernet enabled cameras are mounted in the carriage doorways, and used to register the numbers of passengers entering and exiting the train at each station. Essentially, this indicates when carriages are full, but the data generated is also being used in statistical analysis to identify passenger trends and behaviour, and so help in the planning of improved train schedules.
Why the 6KQ?
A key requirement of the Ethernet switch for this application was its ability to be powered directly from the 110V auxiliary supply, eliminating the need for costly voltage converters. As well as meeting this, the 6KQ also complies with EN50155 for electronic railroad applications, a standard that demands reliable system operation in conditions of high humidity, extremes of temperature (–40 to +85°C), high levels of shock and vibration, as well as power fluctuations.
In addition, EN50155 prohibits the use of fans in train electronics; only passive cooling technologies are permitted.
The IP53 sealed, fan-less 6KQ meets all these requirements. Moreover, as a precautionary measure, EN50155 suggests the use of protective coatings for PCBs in electronic products destined for railway applications, a requirement that is met by GarrettCom’s offer of optional conformal coatings for its products.
The 6KQ is a small form-factor, Gigabit Ethernet switch suitable for demanding applications. It offers a maximum of 12 ports, and can be configured with user-selected combinations of 10Mb, 100Mb and Gigabit fibre ports of any connector type. Copper port options include 10/100/1000 RJ-45, as well as eight 10/100 PoE (power over Ethernet) ports. The device is designed to handle stressful workload mixtures of high-burst data traffic and priority streaming traffic.
GarrettCom Europe is no stranger to the rail industry, having served numerous railway networking projects throughout the world - and for some of the biggest names in the industry. In addition to DSB, the company has supplied managed Ethernet switches to QinetiQ Rail in the UK, Sturkton in the Netherlands and RUF in Switzerland. TGV in France and the Milan and Florence metro systems also number among the company’s clients.
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