Sydney Trains – Management of Assessing Condition of Railway Signalling Systems; Development of a roadmap for life extension and renewals


1.  Summary of project, product, framework

In this project, a framework has been developed to determine the long-term roadmap for renewal of railway signalling systems on the Sydney Trains network. Equipment from different eras is in use including mechanical, electro-mechanical, relay technology and computer-based technology. The framework balances the various drivers of system safety, reliability, life expiry, maintainability, operational and performance requirements whilst managing obsolescence and delivering within constrained funding and resource. A range of asset management tools were used to develop a robust program that met the asset needs and those of the various stakeholders, as well as those of the customers.

2.  Description of project or framework addressing the assessment criteria:                               

This submission is for the framework to enable the development of the roadmap for renewal of signalling interlockings on the Sydney Trains network. This comprises over 1,500km of electrified railway which is used for commuter trains, intercity and regional trains and freight operations. A range of signalling systems are in operation including technologies from different eras as follows:

  • Mechanical and electro-mechanical – 1800s – 1930s – 6% of the network
  • Relay interlockings – 1950s – early 1990s – 43%
  • Computer-based interlockings (CBI) 1990s – present day – 51%

The mechanical and electromechanical systems are life expired, maintenance intensive and form the cornerstone of the current renewal projects; however the relay interlockings with a 40-45 year design life and the computer-based interlockings with a 20-25 year life are mostly expected to reach life expiry over the next decade. The renewal of these places a significant burden on funding required, with an investment of the order of $1.5bn over the next 10 years. The delivery of this work will also put pressure on industry resources and whilst the work is being carried out, it is essential to ensure the systems remain safe and reliable to provide the required service levels for the network.

Consequently it has been necessary to develop a roadmap which correctly prioritises the asset renewals based on asset risks and operational priorities that fits within the available funding envelope and delivery capacity of the industry.

Sydney Trains has developed an Asset Management Framework as part of the Asset Management System. The roadmap supports many of the objectives within the system including those related to customer satisfaction, future network capacity, reduced maintenance costs, the use of asset condition and criticality information for decision making, network safety and obsolescence management. It is therefore an integral document that aligns with our strategy for asset management going forward.

This submission details the methodologies and tools used to develop the long-term roadmap for asset renewals to address the above factors and ensure the required service levels are maintained.

This required a detailed understanding of the requirements which included initial and ongoing costs, operational and performance requirements, asset condition and remaining useful life, risks, safety requirements, available funding and industry resource capability. This was captured through analysis and stakeholder workshops, but the asset condition and lifecycle costing analysis required the application of asset management tools – both developed internally and by external asset management consultancies.

The operating environment is complex with a range of internal and external stakeholders. The internal stakeholders include operations, maintenance, engineering, major works delivery, future network planning, commercial and asset management. The external stakeholders include Transport for NSW – consisting of long-term strategic planning, major project delivery. The organisation represents the State government and customer interests. Consequently, significant effort is required to consider the requirements of each stakeholder and develop a program which aligns with the various needs.

The application of the structured process, along with the use of the tools enabled a renewals roadmap to be developed which the operations, maintenance, engineering and asset management stakeholders could align to as it was clear that the decisions were based on robust technical analysis and information.

Specifically, the framework was developed using the following inputs:

  • Stakeholder workshops
  • Asset condition and criticality analysis, based on field assessments, using the Sydney Trains Asset Condition Assessment and Analysis (ACAA)
  • Prioritisation, using the Sydney Trains Enterprise Risk Management (ERM) process
  • Lifecycle assessment using the SALVO (Strategic Asset Lifecycle Value Optimisation) process and DST (Decision Support Tool), both developed by TWPL.
  • Assessment of funding availability and industry resource levels

One of the difficulties to be overcome was that the signalling interlockings are critical assets to the reliability and safety of the network. Projects to renew interlockings typically take four years from concept to commissioning. Renewal projects must therefore be commenced early enough to be completed before the assets fail, although the exact point of failure is hard to predict as it is unacceptable for rail networks to permit interlockings to reach the point of complete failure, so minimal information is available about interlocking degradation close to the point of failure (Resnikoff’s Conundrum).

To address this issue, both the ACAA tool and the DST model were used to provide information on the remaining life of the assets. The ACAA tool is based on field assessment of a number of parameters of the system. The DST model uses asset renewal and ongoing costs and risks. It also models future failure rates and costs based on historic trends and provides for uncertainties in data (the output is shown in figure 1).

The output of both ACAA and DST projected a similar remaining life for interlockings. This was sense checked with maintenance engineers. The remaining life from the tools was greater than the engineers had initially considered, however on detailed analysis it was agreed that the results were reasonable. The other interesting finding from the DST model was that there is a wide range of timings for the optimum renewal time for the interlocking assessed between 12 and 30 years. This is where the overall costs of risk and renewal expenditure do not change significantly. This allows the renewal timing to be optimised based on other factors including operational requirements, the timing of major capital projects, funding and resource availability.

Armed with the information from the modelling and assessments, the roadmap was then compiled to determine the projects to be undertaken and their timing. This underpins the long-term strategy for the signalling and control systems Asset Management Plan. An extract of the roadmap is included as figure 2.

Since developing the roadmap, periodic reviews have been carried out twice a year; these have focused on emerging requirements and project progress. This has only required minor changes to the roadmap and has allowed teams to focus on delivery rather than changes to projects improving the efficiency of project delivery.

3.  Opinion as to specific contribution made by the nominated individual/team/organisation

The long-term renewal plan had been subject to a number of changes over recent years based on competing priorities and it was therefore necessary to develop a robust and structured process so that a roadmap could be developed that correctly balanced the risks and performance requirements. Subsequently the focus could be on delivery of the program in a more efficient manner by avoiding change and rework.

In developing the framework, the existing data was collected but it was also necessary to identify other information that would be required. This included asset condition information, information about future network requirements, funding availability and industry delivery capacity.

It was also necessary to undertake analysis about future asset degradation/lifecycle modelling and carry out a risk-based prioritisation assessment. For most of the modelling and assessments undertaken, existing tools which were in use in Sydney Trains were applied, although the ACAA process was revised to better cater for the needs. In the case of the lifecycle modelling, the DST tool (Decision Support Tool) and SALVO (Strategic Asset Lifecycle Value Optimisation) process developed by TWPL was used. The output of the analysis was then used to develop the roadmap of projects and the timescales were then applied based on funding available and resource capability.

The combination of the above tools and models, coupled with stakeholder workshops allowed the development of a roadmap which was based on robust analysis and consequently was accepted by stakeholders in operations and maintenance functions who had previously had varying views over priorities. Of course, the outputs were sense checked through engineering reviews, but the process had enabled a consensus to be reached.

Periodically, the roadmap and prioritisation has been reviewed to account for changes in requirements and issues encountered during project delivery, however the roadmap has remained largely stable since the initial publication. A high level and a detailed view have been produced to meet the needs of various stakeholders and for effective communication of the strategy adopted.

This novel approach, which considers assets using different technologies from different eras and applying the tools described, aligns with Sydney Trains asset management objectives. It has allowed decisions to be made supported by data and analysis to align renewals with major capital investment projects and ensure investment is directed to ensure overall best value, minimising risk across the network. It is considered best practice within the organisation for long-term planning going forward.

4.  General comments

The diagram below, figure 1, shows the DST analysis of the lifecycle costing analysis. This includes asset renewal costs and asset failure costs and risks. The total (black) line shows the optimum time to renew the assets based on the cost and risk assessment.

Figure 1: The DST model for interlocking replacement and risk

The diagram below, figure 2, is an extract from the Signals and Control Systems Major Projects 10 Year Roadmap. This shows the high level program based on the analysis and stakeholder workshops undertaken.

Figure 2: Extract from the Signals and Control Systems Major Projects 10 Year Roadmap

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