When you consider rail applications, heavy duty, harsh environment connectors immediately come to mind. Power connectors must be ultra-reliable and rugged enough to withstand high levels of shock and vibration. But increasingly rail and other mass transportation systems also require high speed comms systems, not only to improve the passenger experience but also to allow smart connectivity control and monitoring systems, and even state of the art security systems to ensure passenger and employee safety.
In this respect, 5G could become a major driving force, but industry experts are already concerned that 5G alone won’t be enough to meet the future demand for cellular connectivity – a 2019 report from Deutsche Bahn found that the projected data demand was not likely to sufficiently support the demand for 27GHz. That’s the reason behind the development of trackside networks that can deliver very high bandwidth connectivity and low latency.
Future Railway Mobile Communication System (FRMCS)
Enter FRMCS (Future Rail Mobile Communication Systems), which is expected to replace existing GSM-R wireless connectivity technology. FRMCS will utilise 5G mobile technology and will have the ability to transmit, receive and use increasing volumes of data, all geared around sustainable transport.
GSM-R equipment is expected to become obsolete by 2030. The International Union of Railways (UIC) sees FRMCS as the vital element to drive the digitalisation of railways, while cellular services will maintain their role in connecting the train to the wayside. FRMCS technology is currently being finalised with first trials due in 2023, and wide-scale deployment targeted between 2025 and 2035.
East Coast Microwave, a division on connector distributor, Powell Electronics, specializes in RF/Microwave connectors, cables and components. The company -m which is now supported across Europe from Powell’s European headquarters in Dublin, Ireland, focuses on three areas:
l Wi-Fi for passengers and staff
l Mobile communication repeater systems
l Carriage bridging wireless data transmission
Wireless networks can be used for a range of applications including on-board ticketing, timetable information and internet for passengers. Multiple antennas per access point provide wireless coverage in the train. The main criteria when selecting antennas are the coverage required in certain parts of the train, and the demand for the latest MIMO (multiple input multiple output) technology.
East Coast Microwave provides a wide range of compact omni-directional and directional antennas for various installation situations plus associated connectors and MIMO technology for higher data rates and greater stability of the wireless network.
Today, passengers expect much more: telephone coverage without dead spots; internet access using 4G and 5G technology; high data transmission rates; and national and international network coverage. The direct use of mobile communication networks in trains presents a problem since the design of railway carriages tends to cause significant attenuation of radio waves. The installation of repeater systems with the latest LTE technology now makes it possible to provide fast, reliable mobile communications inside the train. Signals are strengthened from the roof antenna using a repeater and distributed to antennas or emitting cables using cables and splitters. East Coast Microwave provides halogen-free RF cables – developed specifically for the rail market – that can include thin, flexible jumper cables for tight radii and low-attenuation feeder cables for larger distances. MIMO technology is available for interior and exterior antennas.
Data can also be transmitted between carriages using antennas rather than cables. This results in lower installation and maintenance costs, particularly when retrofitting. Less effort is also required to couple and uncouple the carriage. The signal is often transmitted from carriage to carriage using Wi-Fi standard 802.11 a/n in the 5 GHz frequency band. This is mainly done to avoid problems between the various communication standards within a train. MIMO antennas also allow larger data volumes to be transmitted.
Surveillance
The development of any CCTV surveillance system demands high quality reliable components matched with superior build quality. This is especially true when the surveillance system is mounted in a challenging passenger train environment. When Petards, the market leader in on-train CCTV solutions secured contracts for their high performance eyeTrain digital surveillance system, they turned to the engineering team at TT electronics for support.
Effective transport surveillance systems have been shown to increase passenger security by deterring crime and anti-social behaviour. The installed systems need to remain operational in fluctuating temperatures and during extreme vibration conditions whilst providing instant high-resolution images direct to the driver and storing them. The team at TT electronics was able to meet these design challenges head-on with a flexible product offering that met the exacting standards of the rail industry. The AB Multipole high speed & signal data connector was selected by Petards for its simple yet robust characteristics.
The innovative connector features a low fire hazard thermoplastic insulator, which is removable for repositioning and can withstand operational temperatures from-55˚C to +125˚C. The connector’s IP67 rating alongside BSEN61373 Cat 1 Class A shock and vibration classification meant it was the ideal solution for several Petards passenger train upgrade projects in 2011.
High-reliability power connectors
Glenair is a primary supplier of interconnect components and systems for Trains for Regional Service (TSR) in Italy. Designed and manufactured in cooperation with AnsaldoBreda and Keller, TSRs are double-deck Electric Multiple Unit trains with distributed power, consisting of two MCH motor coaches with driver’s cabs and one or more intermediate motor coaches. The traction unit’s composition can be varied from 3 to 6 motor coaches to maintain constant performance. Two or more traction units can be coupled and remote controlled, up to 12 motor coaches. The installation of the train’s furnishings allows easy modification of the seat layout, and the ability to substitute seats with a baggage compartment, folding seats, or lockers. An IGBT traction inverter is installed in each motor coach. Each of these water-cooled inverters feeds two three-phase asynchronous motors. Furthermore, two static groups (3 kV DC/380 V AC 50 Hz) for auxiliary services, each equipped with a battery charter, are installed on the train. Every TSR is equipped with mechanical disc braking on each axle and regenerative electric braking, with reserve rheostat, on each motor axle. The TSR Train cars manufactured in cooperation by AnsaldoBreda and Keller
Glenair’s IRT Series power connectors for the connection of power cables in rolling stock is a critical application. Beyond specific parameters like voltage, current, or watertight sealing, other application requirements must be considered: environment and operating conditions, robustness, handling, and other customer specifications. The IRT connector series is one of the most popular connection systems used around the world, and is able to satisfy all of the common parameters from different railway authorities. Glenair is able to develop customized connectors for specific applications, certifying the products according to your unique requirements.
Powell Electronics stocks and supports a wide range of interconnection solutions for rail at its new EU European facility in Ireland.
