Barmouth to Llanaber – Emergency Repair Works

When heavy storms pounded the UK in 2014, Network Rail commissioned Griffiths to undertake the majority of storm damage repairs around Wales’ coastal railway lines. Nowhere was this challenge greater than at Llanaber, near Barmouth.

Client: Network Rail
Location: Llanaber, Nr Barmouth, Gwynedd
Completion Date: June 2014
Value: £3.5m
Contract: NR9 - Design & Construct

Like much of the UK’s coastline, the Cambrian Coast of Cardigan Bay in Wales took a heavy beating in the January storms of 2014.

A long section of the Cambrian Line runs along this coastline and a 1,600m stretch near to the village of Llanaber was particularly hard hit. The track was moved 2.5m sideways by a tidal surge and there was significant damage to sea defences and embankments. A large 35m hole was created in a 500m long concrete sea wall close to Llanaber Station, allowing wave action to wash out the embankment, leaving the railway track suspended.

An estimated 3,000 tonnes of ballast along this stretch was washed away, with a further 5,000 tonnes of debris, including rock armour deposited on the line. Such was the extent of the damage at this site and the monumental task of reinstatement, the line was closed for five months.

As this stretch of coastline is a Site of Special Scientific Interest (SSSI), it was necessary for Griffiths to liaise with Natural Resources Wales to agree the reinstatement design, construction methodology and how it would minimise the impact on the beach. It was also necessary to secure a Natural Resources Wales licence for the work.

One of the main challenges was getting plant and materials to the damaged area and working within time constraints governed by tides.

To overcome this, Griffiths used existing rock armour to create a ramp and cofferdam on the beach next to the end of the damaged sea wall. This avoided the need to continually move heavy plant along the beach from the only access point 900m away. It also protected the team from the effects of the tide and gave them more time to carry out the work.

A significant part of the repair work was the demolition and reconstruction of the concrete retaining wall and infill the large void created by the tidal surge. This task

required 1,500m3 of reinforced concrete and around 1,000 tonnes of fill material. The existing concrete protection was extended over the remaining 20m of the wall.

Displaced rock armour was repositioned against the sea wall adjacent to the slipway access point. Meanwhile, new rock armour was placed alongside the crest of the northern sea wall to increase the level of protection to the railway line. A damaged fence line was also reinstated to a higher standard.

In total, 9,000 tonnes of rock armour, 4,500 tonnes of ballast, 2,500 tonnes of riprap, 1km of new track, 900m of earthworks regrading, three level crossing reinstatements and 1,500m of new line-side fencing was required to reinstate this section of the Cambrian Line.

Work commenced on the 10th February, and the line was re-opened on the 1st May 2014, two weeks earlier than planned. Remaining engineering works were completed by the 20th June.

The completed site at Llanaber is a model of project delivery. The scope of work, design and delivery is of great quality.
There is a real requirement to capture this completed item of work and use it as the model for all project delivery sites.

Lee Green, Network Rail Route Manager (Wales)

 

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