April 2013

Banking on Concrete Blocks to Stabilise Railway Tracks

With the heavy rain and harsh wintery weather of the past few months causing an increasing number of landslides and embankment failures, a number of rail routes across the UK have been hit, leading to disruptions and delays to services, the need to carry out urgent repair works, and in some cases costly line closures. In this article, Owen Batham, Sales and Marketing Director of Elite Precast Concrete, outlines how a form of ‘grown up Lego blocks’ already proving a huge success in stabilising embankments in the road transport industry could have a similar impact on the railways, as well as bringing a whole host of additional benefits too…

“Over the past few months, there have been a series of high-profile cases where landslides, mudslides, or collapsed embankments have caused chaos on the rail network. Last summer, a train ran over unsupported tracks after an embankment failure in Knockmore, Northern Ireland, while within the space of a few weeks in November and December, landslides resulted in major disruptions to lines at Westerleigh near Bristol, and in Leicestershire – the latter incident leading to the derailment of a freight train and a closure of the line for 10 days. Luckily enough, such unpleasant episodes haven’t led to any deaths or serious injuries, but the disruption and delay to service, along with the requirement to carry out the necessary emergency repairs, are headaches that the industry could well do without. It also raises questions regarding the effectiveness of current embankment retention techniques.

The road industry has faced similar challenges relating to stabilising embankments over the years, and the solution they often turn to – using robust interlocking precast concrete blocks – could provide a more effective, not to mention quicker and less labour-intensive, answer for the rail sector too.  Commonly on railways, stabilising embankments requires a team of contractors carrying out extensive civil engineering at locations which are often remote and/or difficult to access. These are time consuming and costly projects. By comparison, using interlocking precast concrete blocks is extremely quick, with 100m2 of embankment retention easily achieved by relatively few operatives and limited equipment – the blocks can even be installed direct from the back of a freight train carriage using a crane.

One of the key benefits using precast concrete blocks for embankment retention provides is the ability to prevent banks both above and below the railway line from subsiding.  In Canada for example, interlocking blocks are also used extensively retain rail ballast and prevent the lines being damaged by any nearby landslides. The blocks are also perfect for constructing ‘refuges’ quickly and easily, again without the need for expensive and time consuming civils.

In our ongoing discussions with Network Rail and other industry insiders, a number of other areas have been identified where using precast concrete blocks could also have a hugely positive impact. Maintaining the nation’s railway network can be a particularly dangerous task, with Department for Transport statistics over the past decade consistently recording a handful of deaths, anything from 150 to 200 serious injuries, plus between 6,000 and 8,000 minor injuries each and every year. Official figures also show as many as 300 accidents a year are caused by passenger and freight trains colliding with objects on the track.

At the moment on most track maintenance jobs, it’s commonplace for a simple line of tape held up between two posts to be put in place to differentiate which side of the line is being worked on. In theory, this tape is meant to prevent workers  from walking out onto the ‘live’ track, while it’s also intended to stop any machinery such as excavators from  accidentally hitting oncoming trains – in reality, this hasn’t always proved to be the case, with some catastrophic (and life-shattering) consequences. Building a robust temporary wall out of Lego precast concrete blocks could be done in under a day, with the blocks transported on the back of the maintenance trains transporting the machinery and equipment. Creating a much more formidable physical barrier than a basic line of tape, such a solution is already protecting a live railway line at the Drax coal-fired power station in Selby, Yorkshire, where we were asked to build a ‘crash wall’ on a sweeping turn at the site entrance to ensure lorries delivering coal couldn’t skid onto the adjacent tracks in icy conditions.

Another area where precast concrete has the potential to be utilised within the rail industry is as a replacement for the steel formwork which is used when casting bridge supports and foundations.  Interlocking blocks can be used as a permanent formwork, with the foundation reinforcing being drilled and fixed into the blocks creating, a monolithic structure. This offers huge savings in plant, equipment and labour compared to having to remove conventional formwork once the foundations have cured.

With examples such as these, and many more exciting ideas to explore in the months to come, it’s clear the precast concrete industry and the rail sector are on the right track towards devising solutions and systems that not only enhance overall safety, but are also quick and cost-effective to implement.”