Finding positives in negative short-circuiting devices

Source: RTM Oct/Nov 2018

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Anything that brings about safety and time-saving benefits is a valued improvement for the rail industry, which is why the introduction of Negative Short-Circuiting Devices (NSCDs) to make isolations safer and faster is being embraced by the industry. Here, RTM finds out how Kier is working with Network Rail to install them in the Wessex region.

At present, to set up a possession short-circuiting is not simple. Straps are required to be placed by a specific team at the outer areas of the required track possession area. To do this, a trained strapping team has to access the track while carrying testing equipment, straps, bar, gloves, brush, a first aid kit and goggles to install short-circuiting straps to the correct area to allow for track possession to be carried out.

This is known as a B2 isolation process, and it relies on staff accessing and understanding the infrastructure to physically apply or remove the multiple straps. This is potentially liable to human error, such as the straps being fitted incorrectly or in the wrong place as part of this necessary practice for ensuring the safety of those working on Network Rail’s tracks.

Changing the game

That is, until now. The introduction of NSCDs and a new isolation process called B4 isolations, will mean the traditional approach to ‘strapping’ will soon be a thing of the past.

Protecting people working on or around the conductor rail from coming into contact with electricity is a key priority for Network Rail and, until now, short circuit straps have been the best option in providing a physical short between the conductor and running rail to allow work to be carried out safely on the tracks. While this has brought safety to those working on any repairs or maintenance, it’s not been ideal for those fitting the straps, who also have to go back and remove them after the work is finished – which brings with it both safety and time issues.

“Although staff are thoroughly trained before undertaking these works, there could be an instance of the strapping team going to the wrong access gate and potentially strapping out at the wrong location,” explains Sam Eversfield, assistant project manager with Kier Rail. “It’s also a practice that is time-consuming for those carrying out work on the tracks – time that can also have a negative impact for the rail companies and their passengers.”

So how will NSCDs make the job both safer and quicker? An NSCD is a switch that provides a short circuit across an electrical section of track. This means that if a train enters the section, or someone inadvertently tries to close the circuit breaker feeding the section, the conductor rail cannot become live and people working on it are kept safe.

With NSCDs, there is a control panel that can be accessed with a flick of a switch by the engineer supervisor. This process is called B4 isolation. They are operated via a local control panel that is located at a point of safety and convenience in and around substations and TP Huts, with several NSCDs being controlled from each panel. It also helps Network Rail to comply with the Electricity at Work Regulations (1989), which require precautions to be taken against the risk of death or personal injury from electricity in work activities.

Faster isolations mean a significantly safer way to isolate the tracks and also an increased time for construction and maintenance activities. Once all the sectional areas are complete, there will be the opportunity to standardise isolation plans across the network.

Kier Rail has been tasked with the installation of the NSCDs as part of its CP5 contract with Network Rail for the Wessex area, which covers Surrey, Berkshire, Hampshire, Dorset, Somerset and Wiltshire. It’s one of the busiest routes on the network, carrying out more than 230 million passenger journeys a year.

Duncan Hall, Kier’s senior operations manager, stressed the importance of this new system: “For Network Rail, this is about meeting current regulations in making rail safer to access. As a Network Rail E&P framework contractor for the last four years – working on the third rail area covering Kent, Sussex and Wessex – we are well positioned to carry out this work. We also have excellent project teams who have the knowledge, competency and skillset to carry out this work.”

Timescales for success

Kier will utilise its expertise within rail, harnessing its experiences with the high voltage cabling upgrade work on the Reading to Waterloo route, to roll out this programme. It is currently working on 26 sites for Phase 1 and another 36 for Phase 2. 

The first phase is due to be completed by the end of March 2019 and will include 198 NSCD units, with Phase 2 including 237. Work has so far covered lines from Waterloo going out through Surrey to Hampshire, and the first isolation has already gone into service. Staff are receiving training and briefing packages on operating NSCDs.

“Installation of the NSCDs is not complicated in itself,” explained Eversfield, “but installing them in a rail setting adds pressure. It’s not hugely complicated, but the work has to be carried out on a Saturday night within tight time constraints to allow for the train companies to reopen lines. The challenge has been in accessing the sites, which are often in the middle of the countryside such as a farmer’s field.” Train-mounted Kirow cranes are used to lift equipment into position. “It has to work like clockwork,” he added.

Network Rail will begin to reap the benefits from this approach. “Possessions will be quicker and contractors will be able to complete more work,” Hall noted. “They will be able to get four-and-a-half hours’ work in, where previously it would have been three-and-a-half. Increasing the safety of possessions and the productivity of the working time will ultimately lead to less disruption for passengers.” 

Kier Rail is part of the Kier Group, a leading infrastructure services, buildings and developments & housing group. The team operates from offices across the UK, including key offices in London for Crossrail, Birmingham for HS2, Cardiff, Bury St Edmunds and its headquarters of Tempsford in Bedfordshire.




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   10/11/2018 at 10:23

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