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The problem solvers – Improving overhead line reliability on the West Coast main line

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The West Coast main line (WCML) has been at the heart of UK railway infrastructure since the early days of rail development, tracking back to the London and Birmingham Railway and its successors. It has always been a mixed-traffic railway with high density usage and, as such, has always shouldered a heavy traffic pattern and heavy wear.

The route was a natural candidate for the earliest 25kV mainline electrification from the late 1950s onwards, culminating in the wires going through to Glasgow in 1974. This electrification involved heavy rebuilding of the formation and the associated fixed infrastructure but, by the early 1990s, was seen as needing further work to meet expectations at the time.

From this period grew the West Coast Route Modernisation Project which, at its core, was intended to bring the route up to the speeds and reliability required from a modern railway in the twenty-first century. The work was completed and the visible outcome is the Pendolino Virgin service, the modern EMUs and the heavy freight movement we see today.

Poor performance

However, the performance of this most vital UK rail corridor has not recently achieved the level required and Network Rail has made the decision to deliver a major investment programme to reduce delays caused by overhead line failures on the busiest section of the line. Following a six month secondment to Network Rail, Chris Gibb, chief operating officer of Virgin Trains, published his recommendations in November 2012 for the way Network Rail could improve the performance of the London end of the line. The report listed overhead line faults as one of the major causes of delay.

Reflecting on the findings, Dyan Crowther, the route managing director for Network Rail, has said: “We are currently delivering a series of projects to improve the performance of our infrastructure on the southern end of the West Coast main line, which is one of Britain’s most vital rail arteries.” The work is part of a £40 million package of investment aimed at improving performance by targeting some of the most common causes of delay.

Previous experience

Before the 2012 Olympics, Network Rail’s Great Eastern lines were the subject of intense scrutiny over reliability to ensure that no delays would occur during the games period. This issue was successfully tackled by the experienced duo of Paul Ramsey and Steve Price. Both have a strong track record in British railway contact system engineering and were ready to tackle a new challenge. So it seemed only natural to ask them to move on to the WCML problem.

Once appointed, they assembled a small team comprising of John Buckner and John Day who literally walked the eighty miles
of route between London and Rugby and identified a series of improvements that could be made to the overhead lines and reduce delays on the southern end of the route. Samantha McGowan joined the team to develop the delivery plan. The funding emerged from a professional design review and analysis of existing fault and failure patterns.

Paul and Steve have a team working on the project combining expertise from Network Rail and SPL Powerlines UK and the works have been in process from late April. Paul emphasised their keenness to get started and this has emerged as a team of 16 staff with four mobile elevated work platforms (MEWPs) and a five-nights-a-week timetable.

From the end of August, an additional resource from ABC (Alstom / Babcock / Costain) became available to work mid-week nights between Bourne End and Rugby.

Problems identified

The team has identified several shortcomings in existing designs which can cause reliability problems. One which showed up in the study is the work-hardening of the catenary – Hanslope, just north of Milton Keynes, was identified as an area of particular risk of this.

A very visible souvenir of early OLE design protocols was the continuing presence of the auxiliary conductor forming what is known as ‘compound’ catenary. This extra wire in the equipment has been seen as a real risk originator and 27 instances of this additional conductor have been identified. The team are planning to remove all of these with the majority scheduled for removal during a New Year blockade.

Another piece of equipment to tackle is the ‘swivel’, an integral part of the contact system and one which has brought risk in the past. Failure of this component can cause the contact system to drop and this had culminated in damage to a train, ironically a diesel-engined Voyager, earlier in the year. A close examination of the engineering involved has led to the fitting of a stainless steel e- clip to retain the swivel pin and this modification forms another part of the menu for improvements.

Similarly, there has been an equipment shortcoming in a twin-clevis fitting. This has led to the total failure of the system in several locations. Paul and Steve were actually witness to the impact of this failure on the North London line – they were on site when there was an event and the balance weights literally hit the floor in front of them! This cast component is now being replaced by a machined type.

Alternative pulleys

A long-known Achilles heel of the original mark one OLE design has been the above boom pulleys. These were very difficult to maintain and caused hardening on the catenary leading to eventual failure.

The West Coast Route Modernisation scheme solution was to install a miniature cantilever on the boom which replaced the pulley and these can now be seen all over the route. The problem with this solution, however, was the time taken to install the piece of equipment – one installation a night being typical. As the survey had identified around 1200 pulleys between Euston and Bourne End, a new solution was required.

Brecknell Willis, the West Country-based electrification equipment specialist worked closely with Network Rail in developing a modified pulley with a deeper groove to allow a catenary line guard to be fitted. This can be installed in around one hour per item, including the fitting of a ‘bird mat’ so necessary to avoid flashover damage when a feathered friend decides to alight in an exposed place!

This modification is not seen as a design change and therefore installation has been treated as a maintenance renewal. Product acceptance was required for the new pulley.

A line cover has been previously installed to cater for limited clearance and to mitigate bird strikes. However, the current design has also led to failures, so installation is not allowed in current schemes. A new design has been developed by Siemens and this is seen as a solution to assisting with situations such as limited-clearance bridges.

Paul and Steve are extremely excited by the whole project and, by the end of week 52 in 2014, it is anticipated that a massive improvement in reliability of the route will have emerged. When talking about the scheme, Paul and Steve describe themselves as ‘problem solvers’. Indeed, that is a most appropriate title for this pair of motivated performance improvers. They will leave a legacy of a West Coast main line even better equipped to serve customers in the twenty- first century!

Report by Peter Stanton



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