Reference Story
SIL 4 PLC interlocking reduces lifecycle costs
New PLC interlocking with COTS safety controllers offers SIL 4 safety and
reduces lifecycle costs by 30%
(Germany, Bruehl, 10/1/2014)
ProRail, the state-owned Dutch railway infrastructure enterprise,
commissioned consulting and engineering firm Movares with
implementing a PLC interlocking based on industrial COTS (commercial
off-the-shelf) hardware. The new interlocking concept relies on a HIMax®
controller system and satisfies ProRail requirements for supplier
independence, safety, availability, easy operation and maintenance, and
lower lifecycle costs, achieving approximately 30% lower costs than
other electronic interlocking solutions. A pilot project was successfully
implemented at the Santpoort Noord railway station. Santpoort Noord is
the first PLC interlocking for main lines that satisfies the requirements of
the highest safety level, SIL 4, in accordance with CENELEC.
ProRail N.V. provides a secure, reliable, punctual and sustainable rail network
and comfortable stations in The Netherlands. The state-owned enterprise
provides services in three business segments: railway infrastructure, railway
network and transport volume.
"We are responsible for the construction and maintenance of the track,”
explains Jorn Pruntel, Department Manager, Railway Signaling Systems, at
ProRail. “We develop new lines and are also responsible for construction of the
railway stations and for everything else in the neighborhood of the tracks. In
addition, administration and safety are among ProRail's tasks. We must ensure
that the lines we take care of have 100% failure-free availability."
Old railway relay interlockings will be replaced
In 2004, ProRail concluded that relay-based interlockings built from 1953 to
1969 needed to be replaced. The old interlockings were not flexible and had
high lifecycle costs. ProRail also faced the burden of being locked into
proprietary systems that depended on specific providers for component
purchase, engineering, maintenance and modifications.
As part of its interlockings replacement program, ProRail intends to replace the
current ATB system with ERTMS, the future European traffic management
system for lines of the trans-European railway network. The new interlocking
systems must satisfy the following requirements: better RAMS (Reliability,
Available, Maintainability, Safety) performance, lower lifecycle costs per train
kilometer, implementation of new functionalities, and a safer work environment
for maintenance personnel on the line.
Lower lifecycle costs through openness
To achieve its RAMS goals and reduce lifecycle costs for its interlockings on
the main lines, ProRail is committed to open technology. The independent
Dutch consulting and engineering firm Movares proposed a solution that would
enable ProRail to meet all of its goals without proprietary solutions and lengthy
vendor lock-ins.
The Movares solution got its start in 2004 with an ambitious R&D project. The
company began developing a new type of PLC railway interlocking solution to
satisfy safety standards and meet the following requirements:

COTS (commercial off-the-shelf) hardware proven in safety-related
applications in other industries

SIL 4 certifiable solution, in accordance with CENELEC, that is based
on open industry standards with interfaces for external devices

High availability and easy plug and play

Numerous I/O and communication interfaces
Through the use of COTS components and supplier independence, Movares
envisioned for its clients a solution to reduce lifecycle costs by 30% or more.
In the search for a suitable supplier for safe controller technology, Movares
discovered HIMA Paul Hildebrandt GmbH. The German-based safety expert
offers safety solutions for interlockings, railway crossings, rolling stock and
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energy supply. HIMA solutions for the railway industry use state-of-the-art
COTS components that are used widely in industrial automation.
Pilot project - Santpoort Noord
In 2009, ProRail commissioned Movares to replace the old relay interlocking at
the Santpoort Noord railway station with a PLC interlocking. The station is on a
main line with intercity traffic – 10 to 12 trains per hour – and freight train
traffic.
Initially, Movares executed the planning with HIMatrix® controllers. After the
more powerful and fully redundant HIMax controller received SIL 4 certification
in February 2011 – the first controller of this type ever to receive SIL 4
certification, as stipulated by CENELEC – Movares transitioned to the newer
controller. Movares quickly discovered that the scalable redundancy of the
HIMax controller made it the right safety solution for railway stations and traffic
hubs on main lines. Because HIMax is certified in accordance with Achilles
Level 1, it also offers the highest level of cybersecurity.
Thanks to its high scalability and easy extensibility, the controller platform is
suitable for large and small interlocking tasks, and also for monitoring railway
crossings and rolling stock applications. Moreover, it is open for ERTMS.
That appealed to ProRail, which wanted the choice of competitive products
and services throughout the lifecycle. The COTS solution requires no
dependence on any single provider, neither for the engineering and
commissioning, nor for changes and maintenance tasks. Modifications can be
easily executed, and every certified engineering firm can work with it.
Thanks to user-friendly functions, HIMax is easy to operate. This helps
drastically reduce the number of application errors. Maintenance tasks for the
redundant controller system are easy to plan. As a plug and play system with
hot-swap functionality, it enables fast, cost-effective replacement of
components during operation, thereby ensuring system availability. If
maintenance is required, the owner can handle it within normal work hours,
while railway operation continues undisturbed. Through the high-level
diagnostics of the entire system, errors are quickly localized, and maintenance
is facilitated. Due to the short delivery times of COTS hardware, spare parts do
not have to be stored.
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Because it was compatible with the existing interlocking system, HIMax was
easily integrated with the existing infrastructure at Santpoort Noord railway
station. The SILworX® engineering tool, used to program HIMax, became a
favorite of Movares engineers.
Movares programmers created about 25 standard function blocks that map
interlocking functions and can be easily adapted to new requirements.
Moreover, the interlocking function blocks improve the test and validation
process for future applications. Programming errors are minimized through the
tested, preprogrammed solutions. Test and commissioning costs are reduced.
30% lower lifecycle costs
"The lifecycle costs of the PLC interlocking are significantly lower than with
other electronic interlockings,” says Jorn Pruntel, Department Manager,
Railway Signaling Systems, at ProRail. The cost reduction of 30% and more
that we calculated occurs through the initial project costs, through significantly
lower maintenance and repair costs, lower costs of training the development
and maintenance teams, and less-expensive COTS hardware.
Pruntel emphasizes the system’s greatest advantage is that it’s not designed
exclusively for ProRail. "The HIMA system is already SIL 4 certified, and
everyone uses the same system. This increases competition. You do not need
to have spare parts in stock, and multiple persons can make changes or
extensions. Thus we have lower costs and can execute maintenance more
quickly, or we can more quickly modify existing systems.”
Smooth operation
The first PLC interlocking has been in operation at Santpoort Noord since July
2012. In December of the same year, ProRail approved implementation of the
PLC interlocking solution from Movares across the entire Dutch railway
network. Movares views the ProRail approval as a breakthrough in the area of
train control. The combination of proven industrial hardware with railwayspecific applications will result in a cost-effective and flexible product.
Since its commissioning, the PLC interlocking has worked reliably and flexibly,
says Pruntel. "We are very satisfied. It is one of the best systems that we
have."
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The next project is already in the starting blocks. By the end of 2014, Movares
will implement a second PLC interlocking with COTS components from HIMA
for ProRail at the Beverwijk railway station. This interlocking is scheduled to
begin operation in 2015.
Authors
Frits Makkinga, Director Innovation &
Business Development, Division Rail,
Movares Nederland B.V.
Peter Musters, Strategic Consultant,
both of Movares Nederland B.V.
About Movares
Movares Nederland B.V. is an independent consulting and engineering firm in
the areas of mobility, heavy rail, light rail, civil infrastructure, urban and
regional planning, water and energy. The Dutch company, headquartered in
Utrecht, plays a leading role in the rail industry as a supplier of project
management, design and engineering of conventional and ERTMS systems. In
the area of train control systems, Movares employees support the
development of rail safety and control systems for railway customers. In that
role they touch every project phase, from concept to commissioning, and
beyond.
Movares Nederland B.V. in Utrecht
About ProRail
ProRail N.V., headquartered in Utrecht, is the largest railway infrastructure
company in the Netherlands. The state-owned enterprise provides services in
the railway infrastructure, railway network and transport volume business
segments. ProRail maintains approximately 7,000 km of railway line.
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