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Maximum of safety and availability in today's interlock/signal-box systems

BÄR Bahnsicherung AG relies on BENNING’s custom-built, modular power supply systems

The next generation of trains is ultra high-speed, energy-efficient and smart. Locomotive drivers are a thing of the past, these trains drive themselves. They will be crossing continents at 400 kmh. The new “Silk Road” China to Europe train project could come to rely on future trains such as these.

A vision such as this will crucially rely on control and safety technology, hand-in-hand with harmonisation of rail traffic worldwide. These aspirations have long been active in Europe. It was in 2019 that the European Rail Agency, originally founded in 2004, came to be awarded official status, with a view to expediting and simplifying the processes that are entailed. There has to be greater safety and inter-operability. These are key aspects of rail traffic which will be strengthened as the result of the Agency’s efforts.

Modernisation is promoted

Switzerland, which is surrounded by EU countries, boasts one of the World’s most intensively utilised rail networks. The limits of capacity are being approached in more and more cases in this region. Swiss experts are hoping that the self-driving train system will enable the benefit of a more dense service schedule, since this will enable higher traffic frequency levels. On the other hand, it is not expected that public service operation, i.e. beyond the confines of test tracks, can be achieved this side of the year 2040.

Costs should be reduced thanks to the “Smartrail 4.0” program, in the short-term and mid-term. Safety will be further enhanced and there will be a massive increase in capacity. The existing control, signalling and interlock techology requires modernisation, or better, complete replacement in order to meet the more stringent demands now on the table in terms of profitability, maximum availability and safety.

Cost levels down; safety levels up.

When it comes to clearing out the old interlock systems and replacing them with new ones, infrastructure operators will not be satisfied with the key factors of high reliability and availability. They also require attractive levels of costs in terms of systems and service life. With a canny eye on just these requirements, BÄR Bahnsicherung AG has developed the electronic EUROLOCKING® programmable logic control system. SIL 4, the highest safety integrity level under the CENELEC system of standards, is achieved. At the same time, it has been possible to achieve a marked reduction in the costs of investment and operation, whilst preserving high availability and quality.

Inclusion of a modular rectifier module from BENNING
Modular rectifier module, output 24 V - 280 A

Operational success

The first EUROLOCKING® systems were installed and commissioned as long ago as the stage of equipping the complex of La-Chaux-de-Fonds (Bellevue station), Montbovon, Châtel-Saint-Denis and Palézieux (all of which are in Switzerland).
EUROLOCKING® systems are of modular construction. This holds many advantages. For one thing, it means that custom solutions can be applied very cost-effectively. Future-proofing is achieved in spades, because these interlock systems are more straightforward to adapt to changes in conditions.

The modular hardware can be expanded or extended entirely according to preference. Changes in software – or expansions to the system at a later date – can be achieved cost-effectively.
Hot-swap functionality and plug & play are amongst the advantageous features provided. Maintenance & repair tasks are simplified, and MTTR (Mean Time To Repair) cycles are competed much more quickly.

Custom solutions

It was at least 4 years ago that BÄR launched its development of the new SIL 4 interlock system. It was not long before it became apparent that equally stringent requirements had to be fulfilled by the power supply system, which was to be protected by the whole interlock system, from suffering power cuts. Once the corresponding evaluation process had been conducted, BÄR opted for collaboration with BENNING. Pride of place went to high product quality and to the supply company’s capability in terms of precisely meeting a client’s specification. Cost was not the only criterion.
For decades now, the BENNING company has excelled in smart solutions for transforming electrical power into versatile or readily storable energy. BENNING’s modular power supply systems offer safety 24/7. They combine the highest levels of cost-effectiveness with maximum reliability and flexibility.

The power supply system which BENNING has designed for the EUROLOCKING® interlock systems is based on a standardised basic module concept. Consequently, it can be adapted to each situation’s requirements on an individual, custom basis.
It is not only the interlock system that is covered, it also provides power for the signals, points and crossings that are operated all along the rail routes. A back-up power time of between one and six hours is normally guaranteed.

Modularity and flexibility

When it comes to re-fitting interlock plant, you often have to allow for interfaces and dependency of peripheral equipment which have expanded as time goes by but, which of course, have not yet been upgraded. For that reason, the system’s DC power supply is not based exclusively on 24 volts, but also covers custom voltage levels such as 48, 60, 72, 84 and 96 volts that clients may rely on.

Essentially, BENNING’s EUROLOCKING® modular power supplies consist of the following:

  • an AC connection and distribution section, including input isolation transformers
  • a modular, 2N redundant, battery-support 24 V DC supply which is based on the TEBECHOP 3000 HDI robust industrial rectifier. This technology employs A & B rails to protect the core of the interlock system, the PLC control system, against grid faults and failures.
  • an ENERTRONIC modular SE AC-UPS system. The UPS system comes with 20kW modules and comprises a modular battery cabinet. It achieves maximum availability (99.9999%) with n+1 redundancy, hot-swap capability and a low MTTR (Mean Time To Repair). Points motors and signal technology are amongst the consumers equipment served by the triple-stage system, beyond the confines of the interlock system itself.*1

Quality that succeeded in convincing BÄR

An overall system which had BÄR convinced in all areas thanks to quality, maximum safety and the highest availability. The result was that the excellent collaboration that had been enjoyed with BENNING was even further enhanced. Now, power supply systems for interlock upgrade projects are being prepared in Palézieux and in Châtel-St-Denis (both of these are in Switzerland) and in Cochabamba (Bolivia). Five other such projects are already in the planning stage.

It must be realised that we have a long way to go before the vision of intercontinental high-speed goods traffic, based on self-driving trains, actually becomes reality.
However, the new, modernised electronic interlock systems, supported by BENNING’s safe and reliable EUROLOCKING® power-supplies, constitute a crucial contribution to the sustained and continuous development of rail traffic. At the same time, they are already reducing the energy consumption required in operating an interlock system, thus contributing to the reduction of our CO2 burden and lowering the consumption of resources.

*1: ENERTRONIC modular SE RAIL represents an optional choice of UPS catering specifically for typical rail industry needs, since it simultaneously stores power from the public grid (400 V / 230 V / 50 Hz) and from the rail grid (230 V / 16.7 Hz).

Inclusion of the ENERTRONIC modular SE with 20 kVA modules and a modular battery cabinet
ENERTRONIC modular SE with 20-kVA modules and a modular battery cabinet

BÄR Bahnsicherung AG
Luppmenstrasse 3
CH-8320 Fehraltorf
Telephone +41 44 956 52 52

BÄR Bahnsicherung reviews its corporate history, going back over 30 years. The company has several sites in Switzerland. From these sites, rail projects for the whole of Switzerland – together with international projects – are worked on.

The majority of private-sector railways in Switzerland, together with SBB, are willing to confirm that they belong to BÄR’s client base.

The range of products & services has been continuously expanded since the time of the company’s foundation and right up to the present day. Although the project work of Domino interlocks (relay tech) took pride of place at the outset, BÄR is now active in all project phases.

With the aid of more than 100 employees, the Company plans, projects, completes, fits and tests railway safety systems and provides support not only in new builds but also in the context of adaptations to existing rail interchange systems, interlocks, train control and management systems.

Further Information

author/contact: Juerg Badertscher
telephone: +41 44 805 75 81

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