WTS is Siemens’ high performance, high availability trackside signalling system for main line railways. WTS is hosted on the proven, flexible and highly reliable Trackguard Westrace MkII platform. With now the addition of PIMs and ROMs, Westrace MkII PIM50 (Parallel Input Modules) and ROM50 (Relay Output Modules) can be used to relock an existing relay room without affecting the outside infrastructure and can also be used to interface existing line circuits at the fringes.

1. siemens.co.uk/rail
Trackguard WTS
An advance in deployed signalling
technology

2. Trackguard WTS (Westrace Trackside
System) is Siemens’ high performance, high
availability trackside signalling system for
main line railways. WTS is hosted on the
proven, flexible and highly reliable
Trackguard Westrace MkII platform, which
has been successfully deployed by Siemens
on metro and main line rail infrastructure
projects around the world since its
introduction in 2010.
It is an evolution in trackside signalling
control providing a flexible, modern,
network-compatible system designed to
replace Trackside Functional Modules
(TFMs), relays, and other legacy equipment
in a wide variety of trackside applications.
WTS delivers better processing performance
and increased I/O interface, communication
and storage options. WTS also improves
availability and provides advanced
diagnostic capabilities.
WTS is a highly flexible system with Input/
Output modules operating at:
-110 volts AC for direct operation of
signalling equipment
- 50 volts DC for re-locking legacy
equipment and fringe interfaces.
Flexible architecture for multiple
applications
WTS applies highly flexible, network-based
communications to allow a range of
signalling architectures to be deployed. This
means complex station layouts can use a
centralised architecture to simplify the
delivery process and reduce project risk. In
lower density areas, I/O modules can be
spread along the trackside as a distributed
architecture to reduce deployment costs.
The centralised and distributed architectures
can be mixed to optimise the solutions for
bespoke requirements.
An improved approach to
railway trackside equipment
The new generation of
signalling trackside
equipment, improving the
performance and
availability of main line rail
networks
WTS rack arrangement -
more performance and
capacity in the same space
used for conventional TFMs
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Benefits
Reduced space constraints
compared to previous systems
Reduced equipment quantities
deliver lower Whole Life Costs
Easy deployment - fully
compatible with existing
interlocking systems
Improved reliability, availability
and maintainability
Faster responses through
faster processing
Increased diagnostics to aid
maintainers and operators
Increased control and power
available with rapid
deployment
PIMs and ROMs offer relock
capability to interface with
legacy equipment

3. Increased availability
WTS I/O modules have already established an
impressive availability record in service
around the world. Parts of the architecture
can be configured with dual-redundant
functionality so, if a module should fail, the
system automatically switches over to the
‘hot-standby’ module and the system
continues in full operation.
Fully compatible design for rapid
deployment
WTS applies existing widely used
interlocking design tools. This means
designers can easily and quickly produce,
check and test data for rapid deployment to
the railway. The transition to WTS from
earlier systems is straightforward and low-
risk.
Safe stable connectivity
WTS has two Processor Modules (PMs) that
work in ‘hot-standby’ mode providing
redundancy. The PMs allow the interlocking
to communicate with the WTS I/O modules
over a standard Ethernet network via the
industry-leading Westrace Network
Communication (WNC) protocol. This
enables trackside optical fibre cables which
can also be used for other communication
functions such as remote condition
monitoring, automatic power
reconfiguration and axle counter systems
management.
Versatile applications
The processing power, reliability and
performance of WTS have been proven in
extreme conditions and demanding climatic
environments from Australia to Norway, and
from high-intensity metro networks to
long-distance, heavy-haul main line
railways.
WTS enables backwards-compatibility and
permits mixed systems to be implemented
Westrace housing - proven
reliability in some of the
world’s harshest
environments
WTS is a highly flexible
system with I/O modules
allowing deployment in
different configurations to
meet all signalling
challenges
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Westrace SOM110 high-
performance module with
PIMs (Parallel Input
Modules) and ROMs (Relay
Output Modules)
with Solid State Interlocking (SSI) TFMs and
WTS, which simplifies the interface to
fringes and existing infrastructure.
Westrace MkII PIM50 (Parallel Input
Modules) and ROM50 (Relay Output
Modules) can be used to relock an existing
relay room without affecting the outside
infrastructure and can also be used to
interface existing line circuits at the fringes.

4. The techniques used to deploy WTS equipment into location
cases, signalling equipment rooms or Relocatable Equipment
Buildings (REBs) allow more functionality to be housed with
no compromise in maintainability.
This provides at least 25% more I/O capacity for location cases
and up to 50% more for REBs in comparable schemes with an
equivalent TFM system. As a result, WTS provides a
subsequent reduction in costs for civil engineering,
installation and on-site test activities.
Delivering benefits in space,
performance, capacity and reliability
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Increased capacity and
performance in
equipment housings

5. In addition to the trackside
footprint savings, WTS
technology saves space in
Signalling Equipment
Rooms compared to a
conventional TFM system
layout
25% more I/O capacity for location cases
Up to 50% more I/O capacity for REBs
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Faster, better performance for
increasing traffic
WTS uses modern technologies to increase
systems’ speed and increase capacity over
other systems. The response times of a
Westlock interlocking working with the WTS
are significantly faster than a Westlock with
a TFM solution. Reduction in operation time
enables greater operational capacity so
more trains can travel through the
infrastructure.
Full compliance with SIL 4 safety
certification
Westrace MkII fully complies with all the
requirements of CENELEC SIL 4
certification.
It uses a two-out-of-two safety
architecture for all modules. Each
module continually checks its own
operation and should an unexpected
event occur, it will shut down without
affecting any other modules.
The Westrace 110V AC Signal Operating
Module (SOM110) and 50V DC Relay
Output Module (ROM50) can use
double-cut circuits to ensure that a
single earth failure does not cause a
wrong-side failure.

6. Designed for improved
maintainability and accurate
diagnostics
WTS includes an extended diagnostic
capability compared to TFMs. Both solutions
use Technicians’ Facility (TF) products, but
information captured for WTS is in far
greater depth. WTS includes individual
bit-status, condition reporting, and internal
register diagnostic information.
WTS presents accurate, detailed information
that enables maintainers to identify the
source of any problem quickly, reducing the
time required to fix a fault and resume
operational service.
WTS system modules use LED indicators on
the front of each module that provide input
and output indications, reducing the
maintainability cost in the future.
WTS uses standardised, templated
equipment housings, an approach that has
prevented re-design costs. As a result,
maintainers can quickly access and
understand the presented information and
so reduce maintenance time.
WTS provides improvements in
operational performance and
management
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(Image above) Enhanced
system diagnostics enable
rapid identification and
isolation of maintenance
issues to reduce the
operator’s risk

7. Added value
WTS technology provides whole life benefit through
increased performance, improved reliability and enhanced
maintainability. Operators benefit from more train path
capacity while improved diagnostics enable engineers to
identify and isolate potential concerns far quicker than
before.
The reduced space footprint delivers a reduction in
equipment housing by up to 50%, facilitating immediate
savings in associated construction and installation costs.
7

8. Siemens Mobility
Rail Automation UK
PO Box 79
Pew Hill
Chippenham
Wiltshire SN15 1JD
UK
www.siemens.co.uk/rail
Contact: info.railautomation.gb@siemens.com
Version 2.0
The information within this document contains general descriptions of the
technical options available. It describes a standard configuration of the WTS
system. Specific client requirements and options may adjust this standard
configuration to meet specific requirements of deployed WTS signalling
projects.