Signal Power Supply (Maintenance and Reactive Works) Framework, Kent

The challenge

Due to a shortage of resources in the Kent area, for some time Network Rail had been unable to carry out the appropriate level of regular, pre-planned maintenance on the county’s critical signalling power supply assets. From missed 5-year cable and electrode testing, to the replacement of fuses and other components, the lack of general upkeep had led to reliability issues and thus a high and unsustainable maintenance burden upon the client. Those works that were completed were carried out on a reactive basis and only once a failure had occurred, leading to passenger disruption that would otherwise have been avoided thanks to a well-planned and continuously delivered programme of proactive maintenance.

Not only were these failures causing reliability issues, due to the sheer number of faults, the effectiveness of Network Rail’s cutting-edge remote condition monitoring (‘Intelligent Infrastructure’) programme was also compromised.

The solution

Coming off the back of these issues, Network Rail appointed Amaro to deliver a 3-year framework to carry out routine inspections of the signal power supply system, as well as the periodic testing and repair of cabling (mainly 650v with some 440v and 230v), transformers, and equipment for all voltages above 175v in accordance with the relevant Network Rail standards.

Located trackside and providing power distribution to the signalling systems, the SPS consists of a power supply derived from a principal supply point (PSP), cabling connecting the PSP to a power pillar and then, via further cabling, to functional supply points (FSPs). The local signalling system is then fed from the FSPs, and the voltage is transformed below 175v to provide power to the various signalling systems.

Now in its 3rd year, since February 2022 an average of 8 highly skilled operatives (rising to 20+ during cable pulls) have been out on track, working midweek nights and weekend shifts:

• Testing cables to ensure they’re fit for purpose
• Identifying and logging any faults
• Fixing minor issues in real time
• Returning later to resolve more serious issues

Backed up by third-party contractors supplying specialist labour, safety critical and site clearance support, in both year 1 and year 2 our team significantly exceeded Network Rail’s target of 500 cables tested per year. In just the 2nd year alone, in fact, the following statistics were achieved:

• Tested 568 signalling power cables
• Carried out 570 PT1 and PT2 (periodic testing in accordance with NR/L2/SIGELP/50000)
• Performed 570 earth electrode tests
• Replaced 21 faulty cables and repaired a further 3
• Attended several reactive sites to carry out in situ repairs

All faults were reported to the client and saw the completion of a Work Arising Input Form (WAIF), providing a summary of the fault, detailing the repairs necessary, and advising as to the appropriate timescales for their completion.

In addition to the planned aspects of the framework, Amaro teams have also responded to a number of emergency or ‘red triage’ events, all of which have required an almost immediate response. And whilst these were triggered by a range of different types of failures, the vast majority were the result of rodent damage or deterioration following extreme weather conditions.

Whilst most of the locations are covered by the client’s Intelligent Infrastructure system, a handful – primarily those using a single phase 400v system – also require the production of a full NICEIC electrical installation condition report (EICR).

The outcome

Whilst Amaro’s involvement in this framework is very much ongoing, works so far have progressed safely, smoothly, and efficiently, with all of the client’s target figures being exceeded. What’s more, for the first time in years, Network Rail’s Intelligent Infrastructure monitoring system has shown a completely clear board, with not a single amber fault in evidence.

Thanks to the hard work, flexibility, and dedication of our team and wider supply chain, the railways through Kent are becoming safer and more reliable, with journey times and passenger experience improving as a result.