Overcoming the Challenges of Delivering a Light Rail System into Service

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Systems Engineering and Assurance practices were used to streamline the transfer into service of new tram lines on the Manchester Metrolink, the UK's largest tram network.

What does it take to get a project ‘over the line’ and deliver a complex multi-disciplined system into service? Using experience gained from a number of rail and transit projects, the authors discuss Systems Engineering and Assurance practices1 and how these practices were used to enable Transport for Greater Manchester (TfGM) to successfully introduce new services on the Manchester Metrolink, which is now the UK’s largest tram network, and to streamline the transfer of the new extensions into service.


Opened in 1992, Manchester Metrolink was the first of the new generation light rail systems to be commissioned in the UK and was central to revitalising public transport within a major UK conurbation (see Figure 1).  The new light rail system became the springboard for investment and re-generation and provided a real transport choice, encouraging a shift from the private car to public transport.

Figure 1 – In 1992 Manchester’s 2nd generation tram system was officially opened.  Former heavy rail lines from Bury and Altrincham were connected together in the city centre.

Manchester Metrolink, building on its initial success, has expanded in three main phases:

  • Phase 1 (1992) was a 29 kilometre (km) line operated by a fleet of 26 trams connecting Altrincham in the southwest and Bury in the north directly with the heart of the city of Manchester and its principal main line railway stations.
  • Phase 2 (2002) extended the network by 8km to Eccles in the west and the tram fleet was further expanded.
  • Phase 3 (2007-2014) was approved for funding in three tranches in 2007, 2009 and 2013 adding up to an investment totalling around £1.4bn (see Figure 2).  This phase provided for: four new principal lines, increased capacity in the city centre, a completely new depot and control centre, investment to modernise the existing 20-year old infrastructure, and a new fleet of trams.  At the time of writing, powers are being sought for a further 5.5km, 6-stop extension through Trafford Park to the west and the fleet is being increased to 120 modern trams.

Figure 2 – The scale and complexity of the Phase 3 Metrolink Extension Programme (MEP) required the application of innovative Systems Engineering and Assurance processes.


The most demanding stage in a project is usually the period leading to handover to the end user and the Metrolink extension projects were no exception.   For the early extensions, the transfer into service took longer and absorbed more resources than initially planned.  The original assumption was that the coordination of the various activities leading to handover into service would be embedded within the infrastructure construction programme.  It was found that, in order to assure the early involvement of all stakeholders who “owned” an activity critical to line opening and to understand and then manage these activities, a process complementary to traditional programme management was required.

In Phase 3, the challenge for the integrated delivery team, comprising both TfGM staff and their delivery partner, Parsons Brinckerhoff (now part of WSP | Parsons Brinckerhoff), was to create a process to track ‘Go-live’ preparedness in a lean, efficient, and complementary manner, without duplication, and embed within it a reporting mechanism in which all programme functions and senior management were engaged.

‘Go-live’ Process

To develop the new process, the first step was to analyse systematically the entirety of the activities on which a successful line opening into passenger service depended.  Systems Engineering and Assurance practices were used to carry out this analysis and are explained in more detail in the authors’ papers presented at the International Council on Systems Engineering (INCOSE) Conference in November 2014, and referenced below.  Once the analysis was completed, Systems Engineering and Assurance principles were also used to develop a logical framework which defined the system breakdown structure (SBS). Related activities were grouped and their relations to key milestones were captured.  The SBS helped to identify engineering stage gates where the critical integration activities occurred in the period leading to passenger service. There were two distinct environments within which activities were managed in the ‘Go-live’ process structure:

  • The Project Environment encompassed all engineering, system, and safety assurance activities associated with the verification and validation of the new, altered, or affected assets.  The key ‘Go-live’ process stages were separated by stage gates where significant integration occurred or where the operations and maintenance environment was affected.
  • The Operations and Maintenance (O&M) Environment included the activities which affected the operation of the expanding network within various functions including operations, maintenance, passenger services, marketing, stakeholder communication, and regulatory obligations.

The framework is shown in Figure 3, where the horizontal bands represent the system breakdown structure (SBS) and the vertical axis represents the order in time when the stage gates (represented by diamond shaped symbols) logically occur. Whilst the detail may not be clear in the figure at this scale it clearly shows the progressive integration on the sub-systems and elements (dark blue diamonds) as the project reaches the main milestones (stage gates) at which a decision to proceed needs to be taken.

Figure 3 – The Go-live’ readiness process showing the relationship between the main stage gates for the four elements of the system (trams, infrastructure, control, and operations) as integration activities occur and the system is proved and brought into service.

Development of the ‘Go-live’ Readiness Tracker

The ‘Go-live’ process was managed by identifying the key activities associated with each environment (Project and O&M) and which stage gate they needed to be substantially completed by, and tracking them at a series of readiness meetings.  The ‘Go-live’ working group (GLWG) held a workshop typically 16 weeks before the planned date for ‘entry into service’ to jointly work through a prepared template and populate it with the activities to become the ‘Go-live’ readiness tracker (GLRT).  Involving all of the essential disciplines was crucial to the success of the process.

Managing the ‘Go-live’ Process

At the regular GLWG meetings the activities on both the ‘Project’ and the ‘O&M’ environment spreadsheets were updated.   In order to provide an appropriate level of confidence in the process, working group participants confirmed completion of their activities by providing evidence, in the form of an email or letter, a report, test certificate, or other form of auditable and traceable record.

The GLRT tool provided graphical indicators that allowed managers to quickly see progress and where there may be problems (see Figure 4)

Reporting was enhanced by including a separate Critical Issues and Actions Register (CIAR) which was a summary of tasks which were delayed or at risk of being delayed and which was updated at each meeting.

Figure 4 – The GLRT tool provides graphical indicators that allow managers to quickly see progress and where there may be problems.


During successive iterations of the process, it became apparent that an area for improvement was the transfer of information about the installed assets. The asset records can vary in quality and detail and exist in a number of different asset and maintenance management systems.  Reviewing and assessing the new asset information for quality and content became an onerous task typically carried out during and after the point of handover.  In the future, contractual arrangements should be structured so that delivery of ‘as-built’ information takes place continuously throughout the project and is aligned with stage payments.  To achieve this, definition of the configuration of the system delivered by the project needs to be readily translated into the equivalent asset, or configuration, management systems of the O&M parties.  It is proposed this will be made easier in future projects by the adoption of building information modelling (BIM) principles and by making BIM principles part of a process for developing asset information in a transferrable form.


The ‘Go-live’ process depended on identifying the key activities which the transfer from project into operations and maintenance depended and bringing them further forward in the schedule.  This in turn depended on the early involvement of all stakeholders in a collaborative way, using a framework shaped by an understanding based on Systems Engineering principles rather than contractual arrangements.  The success of this approach has been demonstrated in practice by the relative ease with which the newer lines have been brought into operation.

This article is based on papers presented at the International Council on Systems Engineering (INCOSE) UK Annual Systems Engineering Conference and the Institution of Engineering and Technology (IET) / Institute of Asset Management (IAM) Annual Conference in November 2014.


- Knott, A., Applying Configuration Management Principles on a large Scale Operational Railway Engineering 2004 Conference, 6 - 7 July 2004, Commonwealth Institute, London.

- Knott, A. and Stubbs, M, Innovative Systems Engineering Practices that Help Manage the Organisational and Technical Complexity of a Modern Railway Project, International Conference on Railway Engineering (ICRE), Hong Kong, 25-27 March 2008.

- Knott, A. and Hodges, B, A Case for System Acceptance - Progressive Assurance Practices on the East London Line Project, International Council of Systems Engineering (INCOSE) International Symposium 2008, Utrecht, Holland, 15-19 June 2008.

- Knott A., Applying Systems Engineering Practices for the Benefit of Large Infrastructure Projects, 12th bi-annual NETLIPSE Meeting and European Infrastructure Procurement Symposium 2012 in Copenhagen, Denmark, 6-8 May 2012, www.netlipse.eu .

- INCOSE Infrastructure Working Group (IWG) Product ‘Guide for the Application of Systems Engineering in Large Infrastructure Projects’, Version 3.0, June 2012.

- INCOSE UK In-Service Systems Working Group ‘Applying Systems Engineering to In-Service Systems – Supplementary Guidance to the INCOSE SE Handbook’, ls-tr-005, Issue 1.0, 3rd April 2010.

- Knott A, Cope A, Hack M, Getting It Over The Line – Delivering a Light Rail System into Service, INCOSE UK ASEC 2014 "Systems Engineering then and now - celebrating 20 years of INCOSE UK" at RAF Cosford, Wolverhampton, Shropshire WV7 3EX on 18th and 19th November 2014.

- Knott A, Cope A, Hack M, Delivering a Light Rail System into Service – Considerations for Effective Asset Management, IET/IAM Asset Management Conference in London on 27 & 28 November 2014.

- Digital Life, Digital Legacy eBook, Parsons Brinckerhoff, June 2014 pbworld.com/digitalpotential.

1  Systems Engineering is an interdisciplinary field of engineering that focuses on how to design and manage complex engineering systems over their life cycles, and Systems Assurance provides the confidence that the Systems Engineering has been completed. 

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