Jubilee & Northern Line Fleet Reliability

London Underground


Automatic Train Control (ATC) signalling was brought into service on the Jubilee line of London Underground in January 2011, followed by the Northern line in stages, completing in June 2014.

The introduction of the new systems along with high performance, high capacity services required an improved approach to maintain high levels of train availability and minimise service disruption. This meant optimising the effectiveness of the maintenance regime and being able to identify and rectify emerging failure modes thus preventing service affecting failures.

CPC Systems Role

London Underground engaged CPC Systems in November 2014 to work with the Jubilee and Northern Line fleet teams to deliver an improved approach to achieving stringent train service performance and availability targets and to optimise the maintenance regime.

CPC Systems set up a central team dedicated to improved service diagnostics and monitoring, including identification and resolution of residual system issues as well as implementing a best-practice approach to the reporting and tracking of recommended improvements. This included:

  • Implementation of condition-based maintenance, reducing unnecessary intrusive maintenance and overhaul costs
  • Implementation of predict and prevent systems for both CBTC systems and other train systems by identifying normal service behaviours and characteristic ‘footprints’ for deviations
  • Generation of a robust baseline of system performance and reliability
  • Pro-active monitoring of system modifications and assuring CBTC or train system changes against defined success criteria
  • Working with and developing the first line maintenance team to be able to:
    • Investigate CBTC service related incidents and identify suitable solutions
    • Maintain KPIs and the CBTC Train Reliability Improvement Plan
  • Independent assurance of investigations undertaken by the fleet team
  • Analysis of large volumes of data from system logs and generation of daily reports

Commission Delivery

CPC Systems deployed a combination of a site resident engineer at each of the main rolling stock depots to work closely with the fleet teams and remote engineers to support background analysis, railway characterisation and ongoing investigations.

CPC Systems implemented Condition Based Maintenance (CBM) using a bespoke Railway Diagnostic Tool (RDT) tailored for the lines, in conjunction with a cloud computing server to automatically generate performance reports and predict and prevent notifications.

Through the railway characterisation, it was possible to set various thresholds whereby degradation of service performance could be identified and trains scheduled back to depot for rectification or local sites addressed prior to a service affecting failure taking place. Application of this technique has drastically reduced the number of failures occurring in service, reduced the amount of delay experienced by the travelling public and reduced maintenance costs. A paper published by the Institution of Engineering and Technology, presented by the CPC Systems team involved, describes the approach in more detail.

CPC Systems also created a three-day intensive training course on the signalling systems and analysis techniques employed by the team. Ten courses were delivered to a total of approximately 40 depot technical staff to achieve more effective knowledge transfer to the in-house staff supporting reliability, increasing the internal competency with a goal of self-sufficiency, which CPC has fully supported through ongoing mentoring of the fleet technical teams.

Some of the CBTC system failures required a more detailed investigation to be undertaken, examining large portions of historical data to generate benchmarks and diagnose system issues. Such highly complex investigations required a detailed system understanding. CPC Systems was in a unique position to support this type of activity which allowed the railway to continue to operate safely without significant disruption.

Unique Added Value

The CPC Systems team has extensive knowledge across railway operation and systems, including rolling stock, signals, control, SCADA and traction power. A number of the team were instrumental in the successful commissioning of both the Jubilee and Northern Lines. Thus the team were in a unique position to provide support to the fleet team using a system-wide approach to improving performance.

CPC Systems developed and deployed an in-house Railway Diagnostic Tool that allowed incidents to be investigated and diagnosed with far greater ease and railway characterisation to take place. The fleet team were trained on use of this tool as part of the competency handover.

Commission results

CPC Systems support for both Jubilee and Northern Lines has been highly successful, with both lines exhibiting record levels of reliability thanks to ongoing monitoring of train health, implementation of condition-based maintenance, predict and prevent systems and resolution of system-wide issues.

CPC Systems and London Underground were shortlisted for maintenance team of the year in the National Railway Awards 2016 on the basis of this innovative and successful approach to maintenance.

This collaborative approach quickly drove up the reliability and performance whilst reducing cost and has since been identified as best practice and replicated across other technical teams within the operational support environment.

Project Overview


Systems management


Transport & Infrastructure


2014 – 2017