InterCityExpress (ICE) trains in Germany travel at up to 350 km/h (217 mph). German railway control centers and the speeding trains exchange data wirelessly. Installations during 2010 and 2011 brought the total number of systems from MEN Mikro Elektronik to more than 500. The company’s CompactPCI form factor systems (Figure 1) are built to fulfill the stringent requirements of the International Railway Industry Standard (IRIS).

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Solving a lengthy problem

The rugged MEN Mikro CompactPCI system reports the status of the carriage and other parameters in real time to the nearest control center (Figure 2). Condition monitoring of the carriage is extremely important for these high-speed trains. To prevent accidents, engineers must know of any imbalance or abnormal wheel temperature values.

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Other, less critical parameters and information that are transmitted in real time includes data on seat reservations, which can be updated while the train is moving.

The European railway infrastructure includes many long tunnels. Wireless transmission inside the tunnel is a problem. Moving very rapidly both within and between radio cells is another problem. GSM-R (the railway variant of GSM) or UMTS typically handle wireless transmission inside the tunnels. WLAN traffic is transported over one of these two networks.

GSM-R is an international wireless communication standard that can successfully communicate between rail and railway control centers at speeds of up to 500 km/h (310 mph) without signal disruptions. GSM-R features include Advanced Speech Call Items (ASCI), Voice Group Call Service (VGCS) for multiple users, Voice Broadcast Service (VBS) for single speakers and multiple listeners, and Railway Emergency Call (REC) for high-priority matters. Antennas inside the tunnels are leaky feeders (coax cables with longitudinal slits for transmit and receive) or multiple antennas, typically 500 m apart.

Dealing with an extended temperature range

MEN Mikro supplies the CompactPCI system ready for use in a ruggedized 19-inch rack-mountable chassis. The 3U CompactPCI F19P CPU card (Figure 3) is based on an Intel Core 2 Duo microprocessor clocked at 1.26 GHz for increased ruggedness. There is 1 GB DDR3 memory on board and two Fast Ethernet ports connected via rugged M12 connectors. To cope with an extended temperature range of up to +85 °C, the CPU board features a side card with an extra-large heat sink. The wireless devices GSM or WLAN (PCIe Mini Cards) are mounted on an F212 3U CompactPCI card. The plug-in 3U power supplies deliver 100 W at 90 percent efficiency.

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Rigorous requirements

All major European railway operators require IRIS approval. An extension of ISO 9001, IRIS is unique to the railway industry. IRIS approval makes a company part of the elite of premier suppliers to the railway industry.

The EN 50155 standard for electronic railroad applications places heavy demands on railway equipment. EN 50155 assumes that electronic systems on trains will need to operate 24 hours a day for 30 years, or approximately 250,000 hours, without failure. This means that train control systems must be designed to withstand the toughest environmental conditions: extended temperature ranges (-40 °C to +85 °C); humidity; vibrations; and power fluctuations. Even heat build-up and therefore energy absorption have to stay within narrow ranges. Failure-prone fans are prohibited in train electronics, and EN 50155 permits only passive cooling technologies. In total EN 50155 and additional requirements for railway electronics are more demanding than similar MIL-STD requirements.

For more information, contact Hermann at hstrass@opensystemsmedia.com