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GoldenPass line: Safety down the line

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The GoldenPass line panoramic train pulls away from the station at Montreux on Lake Geneva at precisely 08:45. Over the next two and half hours, the train will wind its way over mountain passes and valleys through one of Switzerland’s most scenic and attractive regions. It will call at Zweisimmen at 10:43 and arrive in Lenk im Simmental at 11:21 – on time. On its journey, the metre-gauge train will have passed a total of 36 villages and around 50 level crossings. Writes Adrian Ludi, Pilz Switzerland

The Compagnie du Chemin de fer Montreux Oberland Bernois (MOB) has been operating a 75-kilometre rail network in Switzerland since 1901, including the line between Montreux – Zweisimmen – Lenk. To survive and prosper, it has to keep costs down in all areas, including railway engineering. Operating and control systems must optimise processes and traffic flow, but in complete safety. This is particularly important in areas of potential hazard, such as those 50 level crossings.

Industrial automation technology for railway systems

Intelis SA is based in Bussigny-près- Lausanne and has specialised in all-round railway control and safety concepts for both private and public train operators since 2007. It developed the INIS-TC remote control system which is responsible for ensuring that rail traffic on the 75 kilometre line from Montreux to Lenk runs smoothly and safely under an operating permit from the Swiss Federal Transport Office (BAV).

PRJH 7 0713 - Intelis Case Study - Image 1 [online]

At the heart of the system is the real-time Ethernet SafetyNET p, running in conjunction with the PSS automation system, both from Pilz. First developed to be flexible and versatile enough to be used on cable cars and dockside cranes, this automation solution is now also being put to use in rail transport.

SafetyNET p connects subsystems over long distances and using various media. PSS 4000 includes various aspects of standard automation and safety within one system, offering the benefits of a decentralised control structure without the complexity that is normally associated with such a system.

In detail, the automation system PSS 4000 consists of multiple hardware and software components, such as the PSS 4000-R rail approved PLC, decentralised I/O system PSSuniversal, plus the real-time Ethernet SafetyNET p and corresponding network components. These can be used to connect other decentralised control systems and input/output modules.

Modules with -R (Railway) in the product name have a particularly robust design. The overall system meets increased safety and environmental requirements up to SIL 4 of CENELEC 5012x.

Phasing out relays

Classic relay technology with positive-guided contacts is still widely used in railway and signal engineering. As part of modernisation measures, however, it is becoming the trend wherever possible to replace this electro-mechanical, cable-intensive hardware with powerful software coupled with an easy-to-use network. This solution is not only more cost-effective, it is more reliable and flexible to future changes.

The initial tasks for Intelis were to work out the potential for automation and to identify all of the potential risks along the single-track route. All points, signal boxes, level crossings, signals, track parts and block signalling systems were considered, along with specific customer requirements, as part of an overall assessment.

“How can we simplify the system? How can we replace automated and conventional relay technology with software? How do we integrate the relay technology that’s still necessary and how can we guarantee safe operation?” asked Roland Balimann, technical manager at Intelis, summarising the questions that were posed at the start of the project.

Intelis started by conducting a feasibility study to look at potentially suitable products and systems on the market. These were assessed to safety level SIL3 for safety-related commands and feedback, adaptability to new and existing protection systems and the ability to use industrial products and systems. The result showed a clear case for the flexible PSS 4000 and SafetyNET p modular automation system from Pilz which Intelis ultimately chose.

Safe data transfer

Today, 17 stations are equipped with the PSSuniversal programmable control unit which has an integrated interface to the signal box.
This sends information to the communication server and also to the programmable safety systems via SafetyNET p. It was here in particular that the modularity of the components proved to be a particular advantage; the inputs and outputs could be configured, in both standard and failsafe modes, with the minimum of wiring. The SafetyNET p network is a closed loop – a fibre-optic cable connects all the components that communicate with each other across the whole route.

Today, dispatchers monitor and control all rail traffic on the line safely and reliably from two central control stations in Montreux and Zweisimmen. They receive regular as well as safety- critical messages which display the status of rail traffic and the signal boxes without feedback and in real-time. If necessary, the dispatcher can actively control rail traffic or take appropriate measures if faults should occur.

gplmz004 [online]

Data exchange is via SafetyNET p which is approved by TÜV to SIL 3.

If a fault should occur anywhere on the loop, data exchange is still guaranteed through intelligent switches. Appropriate operator panels are used to visualise information and operating states, graphically represent the stations and display alarm and event messages. But safety is always the priority – the PSSuniversal head modules on site check whether a half barrier is closed or a track section is actually free, for example.

Easily integrated into existing networks

Intelis has been using products and solutions from automation specialists Ostfildern, near Stuttgart, for some time. Ultimately, it’s to do with having industry-proven products that have already demonstrated their safety and reliability.

“The modular design of the PSS 4000 automation system offers users many benefits: they only buy what they actually need; the system is future-proof and can grow to suit requirements. What’s more, solutions can easily be integrated into existing networks and can also be quickly installed using SafetyNET p. Ultimately, the price/performance ratio is simply right,” explained Roland Balimann.

“Something else that we value in our co-operation with Pilz is the fact that the company is always open to suggestions on ways to optimise the system. As a result, we are always able to offer customers solutions that use state-of-the-art technology,” Roland Balimann summarised.

It’s a partnership of equals which, with new projects coming up, is set to continue. Soon, the funicular that connects to the railway line in Les Avants will also be integrated into the INIS-TC remote control system, adding even more control and flexibility to the network


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