Upgrading, adding new electronics and maximising limited space in on-board railway applications
Dave Martin – Director of Business Development – Foremost Electronics
Macro trends such as urbanization, the Industrial Internet of Things (IIoT) and Smart Connected Railways and Cities have spurred the rail industry to make key changes and upgrades in recent years and plan for the future move to 4G-LTE or 5G for communications. Increased political support for energy savings and more environmentally friendly modes of transport such as high-speed rail has increased government spending on infrastructure projects.
The demand for improved infrastructure is also driven by the continued urbanization of rapidly developing regions in Asia and South America. Urban rail is set to grow at an average of 5% per year through to 2025 according to SCI Verkehr1. Increasing passenger numbers and generating greater revenue has also driven operators to look for other opportunities to increase efficiency and profitability which can be difficult with aging infrastructure in place.
Greater connected solutions are enabling key efficiencies but also present new unique design challenges. The IIoT has gained importance in railways around the world. Smart trains benefit from new interconnected systems that are improving safety, security, scheduling, enabling better signalling capabilities and enhancing the passenger experience while optimizing efficiency and improving the overall lifecycle cost of the infrastructure. Interconnectivity has enabled railway operators to move from reactive maintenance to proactive, predictive and preventative maintenance schemes allowing operators to avoid unplanned downtime and optimize utilization of manpower resources and efficient stocking of spare parts.
Modernizing aging equipment on existing rolling stock presents unique challenges such as installing more electronics in onboard locations where space is at a premium. Adding greater numbers of electronic systems on board is a balancing act to maximize space while still creating passenger and operator friendly interiors. Adding new electronic systems also introduces greater electromagnetic complexity. EMC protection is becoming more and more important to ensuring the safe operation of these systems.
Foremost Electronics, working together with nVent SCRHOFF, are able to deliver railway certified, robust, safe equipment designs while overcoming the challenges presented by upgrading legacy equipment or adding new IIoT connected devices.
Examples of nVent SCRHOFF solutions for modernising rolling stock include:
1 – Overcoming space limitations of a new train control unit located in driver’s cab.
A major rolling stock provider needed to upgrade the electronics of a control unit located in the cabin of the train while allowing the systems in the on-board rack to be fully accessible. Enclosure width was a key concern for the design engineers as a standard width cabinet or rack would protrude into the aisle-way obstructing a safe pathway for the driver.
Accessing electronics from the driver’s cab was also a critical part of the design. The design team leveraged the nVent SCHROFF Varistar cabinet platform which offered a space-saving solution for the on-board electronics. nVent SCHROFF Varistar is a versatile and flexible electronics cabinet solution frequently used in railway applications.
The final design minimized the footprint of the electronics cabinet while allowing easy access to the panels inside. The nVent SCHROFF Varistar enclosure included a swing frame. In a swing frame configuration all of the electronics is fitted to the door itself and swings open to allow access to the back panel, which typically contains wiring to inputs/outputs, and is necessary for maintenance. In a conventional enclosure operators would need to remove the electronics located in the front of the rack to access the electronics at the back which would be time consuming and puts the electronics at greater risk of damage during re-installation.
Mounting the electronics perpendicular to the back wall was not possible as it would have obstructed the aisle way. With the flexible, modular design of the Varistar cabinet, configuring a swing frame was a simple modification, and is one of many customizable assembly options. Additionally, selecting a modular cabinet platform gives design engineers the ability to meet specific needs with standard part components, providing a more cost effective solution than total customization.
2 – Vehicle On-Board Computer (VOBC) for signalling – using limited on-board space while saving transport costs
The design team’s goals were to simplify and reduce the cost of an on board cabinet by introducing a design that could be shipped flat packed anywhere in the world and assembled efficiently and easily on site. The VOBC electronics housed in the bolted frame rack could be used for a number of critical signalling applications including monitoring train position and speed status. The innovative space-saving, bolted frame rack from nVent SCHROFF was selected for this application.
The resulting rack design is unique as it is bolted together instead of being welded. The bolted design provides a compact solution that can be shipped flat-packed saving on shipping and storage costs. The rack is then assembled on site, making the installation easier and faster in the confined space of the train. The ability to assemble the rack on-board the train is easier and safer than moving a fully loaded rack through confined spaces for installation. The nVent bolted frame has been designed and tested to AREMA and CENELEC shock and vibration specifications and provides a robust solution for housing sensitive electronics. The bolted frame rack is based on a modular platform, allowing engineers to easily configure a solution that can help minimize rack’s overall footprint.
3 – Upgrade of signalling electronics – housing new CBTC technology in existing infrastructure systems
As electronic systems are becoming more and more compact, the need for smaller, modular rack solutions has grown and are often required in footprints smaller than 9U in height. Innovative On-Board Racks (OBR) from nVent SCHROFF bring space-saving efficiency to on-board electronics and can also reduce transportation costs A more compact rack enables mounting in locations previously not available such as on the floor, beneath a seat or in the ceiling of a train.
Design engineers not only face mounting equipment in a limited amount of space but also must consider the ease of installation. A signalling provider working to upgrade several lines of a major Asian city’s metro network with the latest CBTC signalling technology had a requirement where the 9U footprint available for the rack was less than that of a standard 19” electronics cabinet. Ease of installation on-board the train was also a concern for the customer. nVent SCHROFF offers a standard, compact rack design that was ideal for this retrofit application and helped the signalling design engineers meet the two challenges of limited space and ease of installation.
This modular, standard rack is a welded, stainless steel design providing durability, shock and vibration resistance, and corrosion resistance and meets AWS and EN 15085 (CL2) standards. The modular platform gave the rolling stock manufacturer the flexibility to leverage a standard product that could easily be configured to fit the installation location’s dimensions. The smaller footprint of the rack is also easier to manage during the electronics integration and installation on the train. Selecting a modular design means On-Board Racks can easily be stacked on top of each other or mounted side by side via a standard ganging kit. The On-Board Rack itself is rigid but is open on all sides to allow the electronics to easily be installed and maintained. The open concept of the design ensures efficient cooling and simple cable management.
4 – On-board computer for driver alerts and train control management system
Another signalling provider needed sub-racks to house the vehicle systems in a bolted frame. The system would be running essential driver alerts such as train position, speed, and automatic braking. nVent SCHROFF offers rugged EuropacPRO sub-racks that can be installed in standard Varistar cabinet solutions, rack-mount or bolted rack frames. Rugged sub-racks are designed to withstand extreme shock and vibrations as well as provide required EMC shielding. nVent SCHROFF has extensive experience working with end user rail standards such as EuropacPRO sub-racks, built specifically to French and Germany railway standards for SNCF and DB railways.
Similar to the On-Board Racks and electronics cabinets, EuropacPRO sub-racks are based on a modular platform, enabling design engineers to easily configure the chassis to meet application requirements like various loading capacities, multiple mounting options, and the overall footprint of the chassis.
5 – Track quality measurement – Withstanding harsh environmental conditions, even underneath the train
With technology and sensor advances, predictive maintenance electronic systems may now need to be mounted in places never considered before – such as outside of the train, exposing the electronics to environmental elements including wind and weather or shock and vibrations. Small form-factor or embedded systems, integrated into a rugged enclosure, are ideal for predictive maintenance applications outside of the train. nVent SCHROFF provides enclosure and system solutions for embedded systems both inside and outside of the train, ultimately enabling rolling stock manufacturers maximize usable on-board space.
One such example is that of a track quality measurement that must be taken from under the train. High-speed data transfer was required as was a robust chassis that could offer high environmental protection up to IP 65 which meant a fan-less, convection cooled solution. Additionally, the enclosure needed to be completely EMC sealed for the 3U standard CompactPCI cards in the 5HP chassis. The rugged enclosure provided a small footprint and met technical requirements.
Withstanding the elements and forces experienced when mounted underneath a passenger train was easily accomplished with the robust design. nVent SCHROFF was not only able to provide the design engineering expertise required to supply the rugged enclosure but also the backplanes for the system. The system operates without downtime and reliably provides the track quality data at high speeds.
Faster availability of state-of-the-art railway technology using online tools and product configurators
Specifying a sub-rack or electronics cabinet can be complex and requires engineers to ensure they select the right product for an application The modular nature of the nVent SCHROFF rack and sub-rack platforms allow versatile combinations, enabling design engineers to implement a range of versions in varying height, width and depth, simply, cost-effectively and with no design outlay. Factors such as electronics load, EMC shielding, and certifications can be taken into account.
The nVent SCHROFF online configuration tools assist with product selection. All configurators have a 3D drag and drop interface that enables users to easily configure a cabinet, sub-rack and front panels. The configurators have a built-in logic to ensure all components in the design are compatible while automatically generating a bill of materials.
Modifications like cut-outs, paint, and even card guide placement in the sub-racks can be defined. Finally, design engineers can also export CAD drawings to be imported into their systems or shared within their organizations.
Conclusion
Market trends such as predictive maintenance, IIoT, and the move to 4G LTE / 5G based communications require design engineers to creatively solve the inherent challenges of adding new electronic systems on board rolling stock with limited space. Whether a new or a retrofitted solution, the need for rugged, compact rack and enclosures will continue to grow as rolling stock manufacturers are pushed to upgrade or add new systems. Modular cabinet and rack products will continue to enable rolling stock and signalling providers to
leverage standard platforms globally to economically meet these challenges. Additionally, the availability of online configuration tools will continue to help engineers configure modular products efficiently. Solid design partnerships between rolling stock providers, signalling manufactures, and electronics providers will ultimately enable the solutions needed to support more interconnected and sophisticated systems moving forward in the rail industry.
Key Specifications met by nVent SCRHOFF enclosures for railway systems:
- IEC 61 587-1 and EN 50155 for smooth performance against shock and vibration
- EN 61000-5-7 and IEC 61587-3 for advanced EMC shielding, up to 10 GHz.
- IEC 60529 for ingress protection, up to IP 55 • EN 45545-2 for ‘low smoke zero halogen’ compliant EMC + IP55 gaskets
- CENELEC EN 50125-3 certification for trackside use (1-3 m from the track)
- CENELEC EN 61373 (Category 1 Class A-B)
- EN 15085 (CL2)
- EN 45545 (Product Class A1 according to EN 13501-1)
- AREMA 11.5.1 class C
Foremost Electronics in collaboration with nVent Schroff can supply all the enclosure requirements for railway electronic systems.
