Ethernet Emerges as the Standard for a Unified Train Network

14 September 2010

GarrettCom Europe’s Sales & Marketing Manager, David Moss, discusses developments in Ethernet switch technology for demanding rail applications.

The modern train is a highly networked environment. Of course there are the train control networks for real-time data management in the control of propulsion, anti-skid systems, brakes, doors, lighting, heating, ventilation, etc. But increasingly, train and network operators are looking to provide passengers with an improved journey experience, focusing on safety, security and efficiency. This has placed an emphasis on enhanced surveillance and infotainment networks.

Ethernet has long been a standard for city-wide and facility-wide security and surveillance networks, as well as for business and industrial information networks. In addition, it has proven its credentials in some of the most demanding real-time control applications at the heart of industry. So it is no surprise that rail operators should be assessing its suitability for on-board networks. And so Ethernet holds the tantalising possibility of offering a single unified network solution for both the train control systems and the security and information systems.

The attractions of Ethernet are clear. With its massive installed base, Ethernet is well understood, widely supported, and highly affordable. Industrial Ethernet has quickly become the de facto standard for demanding industry networks, with infrastructure components such as Ethernet switches and routers now able to offer the degree of ruggedness over standard office products to address the rigours of the plant floor, and deliver a high performance, standardised, open communications platform that is readily scalable and very low risk.

Mobile networking architectures, though, are a completely different ball game, where the effects of shock and vibration, and the requirement for absolute reliability in the most challenging of environments and ambient conditions take the stresses on Ethernet devices such as switches to a whole new level.

So to address the multiple networking needs on trains, Ethernet systems must be able to deliver real-time performance for control systems, bandwidth and multi-cast management capabilities for video data typical in CCTV systems, and the general VLAN requirements for information and entertainment systems, and combine all of this with the ability to withstand the high levels of shock and vibration typical in rail applications.

The rail industry standard for electronic components – EN50155 – introduces stringent demands for reliability, covering humidity, extended temperature range (–40 to +85°C), shock, vibration and power fluctuations. In addition, EN50155 prohibits the use of fans in train electronics: only passive cooling technologies are permitted. The availability of Ethernet switches from companies such as GarrettCom Europe that meet these needs have provided the driving impetus for train operators to begin to move to Ethernet – first for security and infotainment networks, and more recently for control systems networks.

Demonstrating GarrettCom Europe’s capability in the rail industry, the company’s 6KQ range of switches are providing providing Danish state rail operator DSB with Ethernet LAN backbones on its fleet of trains. The 6KQ switches are used to realise 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 6KQ met DSB’s need for a compact, cost-effective 10-port Ethernet switch, with Gigabit bandwidth, in a hardened package with the assurance of EN50155 certification for railway applications. A 6KQ switch is mounted in each carriage, and the switches are linked in a bus topology, providing an Ethernet backbone along the length of the train.

Of particular interest in the DSB application is the implementation of passenger counting technology. 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. Not only does this indicate 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.

Where absolute security and reliability are paramount, and for networking applications characterised by high levels of vibration and high bandwidth, GarrettCom Europe has introduced the 6KM Ethernet switch, featuring secure M12 connectors instead of the standard RJ45. These rugged, industrial switches are purpose-built to withstand shock and vibration in harsh mobile environments such as train carriages.

Hardened for industrial use in the most demanding environments, the 6KM meets EN50155 and EN50121-4 standards for use in rail applications. A hardened steel case provides IP52 environmental protection, and also acts as a heat sink, eliminating the need for internal fans and further boosting operational reliability.

EN50155 as a precautionary measure suggests the use of protective coatings for PCBs in electronic products to counteract corrosive atmospheres that are often present in railroad applications. GarrettCom Europe offers two conformal coating options for the 6KM, with a light duty coating to protect against humidity and a heavy duty coating to provide ultimate protection challenging applications.

The best commercial Ethernet switches – as epitomised by the latest products from GarrettCom Europe – pass MIL-standard shock and vibration testing, demonstrating their suitability for both airborne and ground-based deployment, and offer extended temperature operation. They offer EMI/RFI interference rejection and protection as standard, and provide conformal coating for protection against high humidity, corrosive chemicals and salt spray. Further, rugged and robust products are available in innovative sealed versions that don’t need internal cooling fans, and will offer dependable operation with MTBF of over 125,000 hours at extended temperatures.

Rail operators are also increasingly looking to Ethernet to support trackside assets, for example for long line public address systems and remote condition monitoring equipment. As well as providing network solutions that are more cost-effective and easier to maintain for today’s needs, these networks also provide significant spare capacity to grow with evolving railway operational requirements.

GarrettCom Europe has an established reputation within the rail industry, having been involved in numerous railway networking projects throughout the world for some of the biggest names in the industry. In addition to DSB, GarrettCom Europe has supplied managed Ethernet switches to QinetiQ Rail in the UK, Sturkton in the Netherlands and RUF in Switzerland, and for TGV lines in France, and the Milan and Florence metro systems in Italy.

GarrettCom will have a presence at the upcoming Innotrans exhibition in Berlin, 21st-24th September 2010. Please feel free to visit us on Stand 102b in Hall 4.2.

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