Designing for rail applications: weight reduction, expanding data capabilities & speeding up train maintenance
01 May 2019
During a rail vehicle’s lifetime, each gram of weight is accelerated & decelerated thousands of times. Heavier vehicles require more energy in order to gather speed, which in turn costs operators more money. According to calculations by railway operators, each kilogram of train weight costs more than £10,000 over an average service life of 40 years.
This article was originally featured in the May 2019 issue of EPDT magazine [read the digital issue]. Sign up to receive your own copy each month.
Currently, there is a drive towards weight reduction, as manufacturers strive to minimise energy consumption and improve efficiencies. As Peter Addison, Market Application Manager – Transportation at industrial connectivity specialists, HARTING explains, the company’s tagline of 'Pushing Performance' represents it challenging itself to regularly innovate on its products and solutions to keep pace with developments and demands in the world of rail transportation.
When it comes to weight reduction, connectors can make a measurable contribution. With the Han-Eco B (Figure 1), HARTING has developed a range of hoods and housings manufactured from high-performance, glass fibre-reinforced, polyamide plastic. This means the range offers substantial weight savings of up to 50% per connector, compared to traditional metal versions.
The Han-Eco range complies with standards IEC 61948 and EN 45545-2 HL3 and is fire-resistant according to UL94 V0. As well as being lightweight, the range also supports modular inserts, meaning data, signal and power can all be combined into one standard-sized industrial connector, further reducing the space required for connectors and simplifying the installation process.
Railway application solutions are always subject to particularly harsh environmental conditions, including vibration, moisture, dirt, heat and cold. This also applies to the connection technology for train control modules. As a result, HARTING has developed a unique full metal housing, made of die-cast zinc.
The housing uses approved standard F and MH crimp connectors in accordance with DIN 41 612, which are fastened without the use of screws. The labyrinth design of the housing safely protects it against electromagnetic influences. These configurations guarantee an electric connection to the cable shielding, and therefore an uninterrupted homogeneous shielding of the housing. This ensures absolute signal integrity in the train control units.
The captive screws are already fastened to the housing and the unassigned cable entries are covered with flexible metal plates, which are easy to assemble and remain securely in place thanks to the mechanical tension.
What’s more, the housing is designed so the cable can be fixed in the housing with a standard cable fastener, providing a simple and cost-effective assembly option.
At the same time as trying to reduce weight, rail operators are faced with the challenge of expanding data capacities on rolling stock, in order to offer high-performance infotainment systems and fast, reliable internet access.
By using the preLink system and EtherRail cables, data networks in trains can be securely built and future-proofed. The central component of the preLink system is the termination block, which makes it easier to create the cable connection. The miniaturised preLink contact block allows you to pre-fabricate data cables outside the carriage, before installing them. After the cables have been laid, the appropriate connector is assembled, depending on the network device to be connected. This method offers flexibility and simplified assembly, making it faster and more reliable.
Interior fitting work in trains is often awkward, due to tight space conditions, and cable ducts, wall ducts and the interior of control cabinets can be difficult to reach. When you’re working in confined spaces, easy installation is crucial, so HARTING has looked at the issue of difficult assemblies. Thanks to the M12 PushPull (Figure 2), there is now a solution which delivers handling, time and reliability benefits.
Traditionally, M12 connectors were locked in place via a screw connection, with a tool being used to achieve the necessary torque. However, this method can be extremely time consuming, especially if 20 ports on a switch need to be mounted in a confined space or from an uncomfortable working position.
The M12 PushPull uses an intuitive, tool-free connection technique that ensures absolute reliability: as the two sections are clicked into place by hand, an audible feedback indicates the connection is secure. As well as simplifying difficult fittings, the tool-free installation method means the assembly density can be substantially increased, helping to save valuable space.
When it comes to train maintenance and servicing, every minute counts. A train being serviced is a train that is not available to passengers – and therefore, one that has a significant impact on costs. In addition, the various components of a train have different maintenance cycles and must be serviced by specialised professionals.
In order to speed up these processes, HARTING has developed a robust UHF RFID (radio frequency identification) reader (Figure 3), which can be used to automatically identify the train and its important components, for instance, the axles and individual carriages, as it enters the maintenance area.
The RFID system notifies engineers about the condition of critical parts which require maintenance. This saves both time and costs, as it allows technicians to focus on the parts that need servicing. Using special robust HARTING transponders, different components of a train can be tagged and clearly identified.
A key benefit of using RFID is, unlike barcodes, you do not need direct line of sight to read the transponder. It’s also possible to read multiple tags at once, with the high-speed technology allowing you to read up to 300 tags per second. Another advantage for the rail industry is that tags can be read at a distance of several metres, even when trains are travelling at over 120mph.
Using special flexible LOCFIELD antennas, the entire RFID system can even be adapted to create reading zones for smart shelves in stores, allowing you to track spare parts in service centres.
Finally, we can also assist with the specialist manufacture of Intercar Jumpers for power and data, which are designed and manufactured at our UK facility in Northampton.
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