The pressure is on. The sea wall was breached by storms on 4 February and the railway has been washed away. Writes Collin Carr
Business in the West Country is suffering and the government is demanding effective engineering solutions that can be quickly activated. Network Rail has set itself a target to reinstate the railway by mid-April and has appointed BAM Nuttall as principal contractor for the work to help them achieve this challenging target.
The damage to this coastal stretch of railway is extensive; more than 80 metres of the sea wall has been breached by the waves and washed out to sea. By mid February, the breach had expanded to more than 90 metres in length and the formation and track ballast behind the wall had been washed out to sea followed by the retaining wall that supported a private roadway and the roadway itself, leaving the houses beyond in a very precarious state.
Apart from the breach described above, there are five other locations between Dawlish and Dawlish Warren where the sea wall has been breached, but so far the damage is not as severe. Also, Dawlish station has taken a battering, the wooden down platform boarding has been ripped out and furnishings badly damaged. Further up the coast in the Teignmouth area, there are concerns about the stability of the sea wall at various locations.
The appalling weather has been relentless and the tides unsympathetic. As BAM Nuttall’s site agent Alastair Morley explained, all parties had to act immediately to protect the formation supporting the houses that were now totally exposed, and they had to do something quickly to prevent further erosion. So after cutting the rails over the breached area, the concrete-sleepered track was laid across the formation to offer added protection. Once the sacrificial track was in place, the whole area was covered in sprayed concrete, offering additional resistance to the next high tide and helping to minimise further destabilisation of the exposed row of houses.
Temporary protective barriers
Whilst this work was underway, a procession of eleven ship containers was brought to site and placed on the footpath in front of the 90
metre breach. The containers were then welded together and filled with rock and rubble gathered from the site. This metal barrier has provided the much needed additional protection so that reconstruction to the damaged area could take place. However, it wasn’t plain sailing, the ferocity of the sea split two containers so running repairs to this temporary barrier has become an essential part of the daily routine. In addition, a scaffolding bridge has been constructed to span the 90 metre gap so that services and signalling equipment can be reinstated and reconnected to the existing infrastructure.
So at the time of writing this article, it appears that a little breathing space has been created and the immediate further erosion has been addressed. There is now a reasonable barrier in place to keep the hostile sea at bay for the time being. Whilst this work was underway, Network Rail was considering what needed to be done to enable all the repair work to be completed and to restore the railway to meet the deadline.
Several other suppliers were needed to support BAM Nuttall as principal contractor so Amalgamated Construction (AMCO) was drafted into the process by Network Rail. One of its teams was carrying out other railway work in the area at a significant site near Tiverton, where they are carrying out repairs to Whiteball Tunnel (as reported in this issue on page 92). AMCO was given the responsibility for repairing the 90 metre breach.
Also, SISK group was brought in to rebuild the down platform which had to be demolished at Dawlish station and carry out other repairs to the station buildings and Up platform.
At a separate site, Dyer & Butler has been drafted in as principal contractor for the repairs to the sea wall between Kennaway Tunnel and Teignmouth station. As the local maintainers, Dyer & Butler will add vital local knowledge and expertise to the team and will also undertake extensive geotechnical works to the cliff face.
In addition to all the work that is taking place on site, Network Rail has procured the services of Tony Gee & Partners to develop a design for repairing the main breach. Although, at the time when this article was written, the design was still in its developmental stage, thoughts were turning towards the construction of a barrier made up from concrete vehicle barriers. These are precast concrete units about 2.5 metres in length, tapered from a base of 700mm down to 300mm and weighing approx.2.5 tonnes.
These units will be fixed to the formation using 36mm diameter dowel pins and tied together using horizontal reinforcement ties. Once this barrier is in place, the void behind will be filled with pumped concrete before reinstating the ballast formation and track. The concrete will also make up the levels for the private road surface to be laid and the retaining wall between the road and rail formation will probably be constructed using precast L-shaped concrete units.
This is a team effort that is calling on total commitment from everyone involved. To ensure that their efforts are coordinated and effective, there is a site meeting every morning with all interested parties attending – including Network Rail’s local track and signalling maintenance teams. This is followed up with another meeting late afternoon to assess progress, consider new developments and address any emerging problems. Meanwhile, there are more than 100 people working a 12-hour shift with a similar number ready to replace them for the next shift.
Between the two shifts, a handover meeting ensures that everyone knows exactly what is going on and what is being planned for the future. However, within this ordered and well managed process, the totally chaotic weather continues to pound the coastline. Alastair emphasised that everyone in the team is determined that nothing will stop them achieving their task of ensuring that trains will be able to run between Newton Abbot and Exeter as soon as humanly possible.
Everyone is doing everything within their powers to deliver what is required and when it is all over, all those involved will deserve a well earned holiday – but definitely not by the seaside.