Coventry, Coventry, CV3 6HE
Redi-Rock™ Retaining Walls
Environmental factors are definitely having an impact on the rail system, with Network Rail actively monitoring climate conditions and the damage they can cause. In 2019, the country experienced the twelfth warmest summer on record, which was closely followed by a period of almost continual wet conditions, saturating much of the UK. Then Storm Ciara and then Storm Dennis hit, flooding many parts of the country, exposing earthwork and causing instability along the tracks.
So when a landslip slows the rail network it causes major disruption, especially when it’s a mainline, connecting London to the midlands and beyond.
The RBS1 is the Birmingham, Rugby and Stafford line, often known as the Birmingham loop. The West Coast mainline (WCML) begins at London Euston, and navigates to the Midlands. At Rugby, it splits into two, with one route going towards Trent Valley, stopping at Nuneaton, Tamworth and Lichfield before reaching Stafford and Crewe. The other goes to Coventry, Birmingham and Wolverhampton, before stopping at Stafford, and that is the Birmingham Loop.
One of the cuttings, which became extremely unstable due to extremes of climate, was near Brandon in Coventry, approximately 86 miles from London. It is known for its Grade 2 listed viaduct, designed by Robert Stephenson and built in 1836 as part of the London and Birmingham Railway.
Network Rail has a call-out contract with J Murphy and Sons, who have depots along the network, enabling them to quickly access emergency works. This has allowed J Murphy and Sons to develop a reputation as one of Network Rail’s preferred contractors for earthworks.
Murphy received the call from Network Rail on the 7th February regarding the landslip, whilst Storm Ciara was still advancing across the country. Murphy duly attended a site meeting to examine the bank slip, which had occurred on the upside of the cutting. A length of approximately 200 metres of cutting was affected.
Murphy opted for a plan to remove the failed slip material and then stabilise the cutting by installing Redi-Rock concrete blocks from Marshalls Civils & Drainage. To allow them to do this, Network Rail arranged emergency possession and isolation for the following night, illuminated the affected section, and positioned team members on site until the project was completed, ensuring no further earthwork movement occurred.
Network Rail imposed a temporary speed restriction on both lines of 20mph (freight) and 50mph (passenger) throughout the cutting.
Senior Asset Engineer Luke Swain from Network Rail and Works Manager Cathal McCann from J Murphy liaised with the Network Rail properties team to organise a land agreement with the farmer/landowner to ensure that access to the site. This included the large 32-tonne excavators and other long reach earth moving machines that were required to carry out the work to reach the site.
With access being critical, J Murphy were instructed to install 150 metres of wooden post and rail fencing to segregate the farmer’s horses from the work area.
Once completed, J Murphy began work, proceeding to establish the extent of the site work required and produce a solution that would offer long-term stability to the area. Their examination of the area showed that more of the cutting had failed and several pre-existing tension cracks were deteriorating, due to the continued bad weather.
Luke Swain from Network Rail commented: “Additional possessions that were needed were quickly supported by the passenger and freight train operators and joint plans, involving a huge amount of additional work, emerged from all parties were agreed, enabling the route to remain open during this period.”
Additional heavy plant, ranging from 13 to 67 tonne excavators were brought in, along with additional road-rail equipment from J Murphy plant depots in Golborne (Wigan), Hemel Hempsted and Cannock.
With a landslip and a storm to deal with J Murphy thought, they had covered all angles, until COVID 19 hit.
J Murphy, Site Manager, Paul Tarbuck led the site, working six to seven days a week to ensure that everything ran smoothly ,and that plant, materials and a skilled workforce were available to continue the project.
As the contractors were using heavy plant and machines operated by individuals working alone, they were able to comply with the social distancing measures imposed. All machine movements were overseen by banksmen, equipped with two-way radios that enabled compliance. J Murphy introduced additional canteens, drying rooms and toilets to comply with social distancing and had all site accommodation cleaned on a daily basis by experienced contract cleaners.
Whilst the storm still battered the site, three more slips were identified and all parties agreed to extend their weekend track possessions to midweek possessions to allow them to install the Redi-Rock concrete blocks throughout the entire length of the 200-metre cutting.
J Murphy procured international designer Bryne Looby, and a design was finalised and signed off. It was agreed to regrade the full length of the upside cutting and install a Marshalls Civils & Drainage Redi-Rock wall at the toe of the cutting. Although other options were considered it soon became clear that Redi-Rock concrete blocks was the only viable option.
The Network Rail approved Redi-Rock retaining wall blocks are ideal for protecting the railway line against erosion, landslips and rocks. John O’Gara, Marshalls Civils & Drainage Specifications Manager, commented, “The big block solution is both quick and easy to install when you have limited track time available and can be dry laid in any weather, which is just as well given the conditions on site.”
Completed in August 2020, the £4.5 million project was hit by everything including a global pandemic.
Luke Swain noted that throughout this challenging period, Murphy had not only provided a critical role as the on-call earthworks contractor for the project, they had also managed this large complex site, in conjunction with a series of other landslips. The landslips were triggered across the region by the winter weather conditions, meaning J Murphy is a crucial element of the supply chain, keeping the railway safe and operational for passengers and freight. Murphy will have a significant part to play in delivering Network Rail’s ambitious geotechnical renewals plan on the North West and Central region.
Given all that is happening in the world today, with COVID-19, lockdown and a global pandemic, it is easy to ignore the day-to-day emergencies, but they don’t just go away. Murphy has clearly thought through the different emergencies that could hijack the UK railway network. It has organised its engineering teams strategically and was ready to respond to whatever Storm Ciara had to offer, helping Network Rail to maintain a pathway for trains to run on one of the most important routes in the railway network, emphasising the value of being prepared to respond to whatever emerges, be it virus or tempest!
To find out more about our Redi-Rock solutions please visit Redi-Rock™ Modular Concrete Walling for Rail Line Protection | Marshalls