Last February, a good portion of the UK land mass appeared to be underwater and the coastline was being buffeted and bashed by storms and unprecedented high tides. This badly affected many costal railways, but perhaps the worst problems that Network Rail had to deal with were in Devon, on the main line running along the exposed and vulnerable sea wall at Dawlish. Writes Colin Carr

The damage to this coastal stretch of railway was extensive. Around 80 metres of the sea wall had initially been breached by the waves and washed out to sea but, by mid February, that breach had expanded to more than 100 metres in length and the formation and track ballast behind the wall had vanished, as had a retaining wall supporting a private roadway and then the roadway itself leaving a substantial number of houses beyond in a very precarious state (issue 113 March 2014).

First 48 hours was critical

It’s now early summer, so The Rail Engineer has been back to Dawlish to meet some of the engineers who were involved in putting the railway back together, to find out what they think about it all now that the adrenalin has settled and they have had time to reflect. Alex Evason was Network Rail’s senior construction manager. He was involved with the repair work throughout the period working for Tom Kirkham, the project manager for the emergency.

Alex explained that the appointment, in the first 48 hours of the emergency, of BAM Nuttall as principal contractor for the main breach of the sea wall and all the additional myriad of sites suffering from the storm damage had been critical. This ensured a clear line of command and responsibility from the start of the repair work.

Daily meetings were established at 9am and 4pm, chaired by BAM Nuttall, to ensure that plans and ideas were shared, understood and resources appropriately allocated. Amalgamated Construction (AMCO) was drafted in to provide additional expertise and support.

Andy Crowley, AMCO’s contracts manager, explained that they needed plant, resources and materials on site as quickly as possible and one of the early challenges was to develop an understanding as to how they could best use the resources available to protect the railway and minimise further deterioration whilst the storms continued to rage. To help this process, Network Rail also procured the services of Tony Gee & Partners to develop a design for repairing the main breach.

The ability for the repair team to easily and securely share large data files such as architectural blue prints with the team on the ground at Dawlish and those working at other locations including BAM Nuttall and Network Rail’s offices was critical. Alongside this was the need to incorporate separate access to site visitors, including members of the Cabinet oversight committee.

IMG_2084 [online]Trellisworks, a specialist wireless connectivity expert, designed and deployed an emergency communication network based around the Pepaves MAX wireless router range. This network was capable of sending and receiving large quantities of data rapidly and reliably, yet also needed to be flexible and resilient enough to cope with the changing situation on site as well as ongoing challenging weather conditions.

Rob Youster, Head of ICT at BAM Nuttall said: “We needed a communication solution that was robust and capable of handling the high-end data needs of the site. It needed to provide secure Wide Area Network (WAN) and wireless access reliably 24×7. The communications network that Trellisworks created was absolutely vital to the smooth running of this project and ensured that the team on site were able to communicate and collaborate effectively with colleagues who were not based at Dawlish.”

“You could smell the gas”

The main breach became known as the “Hole” and in the early days it was the main focus of attention. Each high tide was washing more of formation away from the railway and the roadway behind. In addition, many of the houses had been badly damaged and they had to be evacuated. Gas, sewage and water were leaking across the site from the houses so something had to be done immediately before the houses started to collapse or the site became too dangerous to work in.

Lenny Wilkinson, BAM Nuttall’s works manager, has a reputation on site for making things happen using a network of good contacts acquired over the years. Whilst working on a previous job in Jersey, Lenny remembered that steel ship containers were being used for protection and he brought this idea for discussion to one of the daily meetings. Within 48 hours, Lenny’s coordination skills ensured that eleven new containers arrived from Southampton docks. They were cut open in preparation for filling with ballast and formation rubble on site then welded together.

Further storms on 14 February extended the “Hole” to more than 100 metres, which meant that more containers were required. Eventually, a total of nineteen sea containers were used to protect the vulnerable sea wall and, although they are now in a dilapidated state, they are still in place acting like one of those medieval shield walls providing a last line of defence. The effectiveness of this defence was discussed at a COBRA meeting chaired by the prime minister… now there’s endorsement for a good idea!

The Army offered its services and brought some interesting proposals. However, although the sea wall probably felt like a war zone, it was a different environment and the materials and skills that the army had at their disposal were not really suited to this particular task.

Relocating plant and resources

Once the containers were in place and absorbing the battering from the sea, work to stabilise the site could commence. AMCO, which had been working 30 miles away in Whiteball tunnel near Taunton (issue 113, March 2014), was able to relocate its plant and spray concrete onto the exposed formation using the now redundant track as additional ballast and reinforcement. This was another critical step that bought precious time.

At its peak, 300 engineers were working day shifts followed by 200 engineers working nights. To ensure that they were able to resource such numbers, it was decided to redefine the site as a ‘High Street’ location rather than a railway location. This was possible as it was no longer a functioning railway and it meant that skilled engineers who had not worked in a railway environment before could do so without any additional site safety training. However, Alex was keen to point out that at no time were safety standards compromised and throughout this intense period of work, carried out in appalling conditions, only two minor injuries (both sprained ankles) were recorded.

Filling the Hole

AMCO as the main contractor, along with BAM, was tasked with acquiring concrete vehicle collision barriers (VCBs) from around the country.

These were placed in the “Hole” and fixed together laterally with dowel pins and 40mm stainless steel transvers bars. Then, more than 5,000 tonnes of C50 concrete, an additional 150 tonnes of steel, and a new 600ft-long section of track were used to complete the repairs.

More than 450 metres of parapet sea wall was either badly damaged or missing altogether along with associated footpaths, walkways and steps. Hanson’s precast concrete works at Derby provided L-shaped units within three weeks. These ranged from 2 to 3.25 metres high, 1.2 to 1.6 metres wide and 1.6 metres long and they were used both behind the parapet sea wall and the retaining wall for the roadway behind. Cornish Concrete produced 260 coping stones weighing 1.8 tonnes each.

Hanson also provided pumped concrete to the site, using highly-skilled professionals concrete pumping services which had the expertise to get the material to this exposed location. This was not an easy matter since the only access way to the “Hole” was down a series of narrow flights of stairs winding between houses on a very steep incline.

Dawlish station repairs

In addition to this major damage at Dawlish, there were at least five other locations between there and Dawlish Warren where the sea wall had also been breached, albeit not as severely. Dawlish station had also taken a battering, the wooden down platform boarding had been ripped out and furnishings badly damaged, and there were concerns about the stability of the sea wall at a number of other locations further up the coast in the Teignmouth area.

The SISK Group carried out repairs and reconstruction of the down platform at Dawlish station while Dyer & Butler focused on other repairs to the sea wall between Parsons Tunnel and Teignmouth station. Lee Davey, senior site agent, explained that they were the local maintainers and so they were able to add vital knowledge and expertise to the team.

More than 37 individual landslips were identified. One, known as the Woodland landslip, was particularly worrying and was one of the reasons why the completion date was at one point revised to 28 April. AMCO’s specialist contractor CAN, working at Woodlands to stabilise the bankslip, reported back-scars that were initially 80 metres long and three to five metres deep. Because of the torrential rain these scars were growing, becoming anything up to ten metres deep, which indicated that there was some serious ground movement taking place.

IMG_2127 [online]Drone technology

AMCO procured the services of a drone that had been used on the previous year’s slip site adjacent to the Woodlands location.The drone was able to take  pictures that confirmed the concern that a 55 metre high cliff was slowly releasing 35,000 tonnes of debris onto the tracks. To deal with this AMCO, then procured the services of the USAR (urban search and rescue) from the Devon & Cornwall Fire Brigade and China Clay, both experts in the field of high-pressure water pumping equipment. This expertise was used to accelerate the failure of the slip by a combination of pumping water into the back-scar to lubricate the slip plain and hydro-cutting the cliff face, as is common practise in the world of quarrying and mining. This proved successful and the debris was then disposed of into the sea with kind permission and approval from the Maritime Marine Organisation.

Dyer & Butler then had to repair the parapet wall that had been damaged by the slip.

So, although the potential slip put back the expected reopening of the line from around mid-March to mid-April, Network Rail was subsequently able to announce that the line would reopen on Friday 4 April in time for the Easter holidays. David Cameron officially declared the line open. The local community laid on an event in the town hall for the Orange Army; clearly they had appreciated all that had been done on their behalf.

It has been a field day for the press with spectacular pictures and videos of a washed away railway protected by a sacrificial wall of ship containers, welded together, filled with rock and rubble and lined up on the footpath in front of the 100 metre breach. It took teamwork to put everything back together, and all those involved commented that everyone pulled together. Frequent mention was made of the many suppliers and sub contractors who played an invaluable part in ensuring that everything possible was done to ensure that the railway was restored as soon as was humanly possible.

Secondary wall

With an overall cost in the region of £35 million, it has been an expensive experience for Network Rail. So what will happen in the future? What has been learnt?

Well, AMCO has now been appointed as principal contractor for the next phase. Approximately £8.5 million is being made available to complete the construction of a secondary wall in front of the original Brunel wall and the plan is to have this secure by the end of the summer. A marine approach to the works will be adopted, with new pre-cast wall sections being lifted in by jack-up-barges to minimise disruption to train services.

Dyer & Butler will continue to work within a budget of £500,000 to carry out day-to-day maintenance including pointing. A five-year plan is being developed to improve the resilience of the wall and there is a feasibility study underway by Tony Gee & Partners to consider the viability of seven alternative routes.

Finally, as Alex pointed out many times, it was fundamentally a team effort with everyone working together to restore a railway for the benefit of the West Country. Alex also added that the local community, particularly hotels and suppliers, did very well out of the disruption and there was a boost for the local economy. It just goes to show that every cloud does have a silver lining of sorts!