Wednesday, 27 April 2016

Settle & Carlisle Railway update

From the Settle & Carlisle Trust
"The Trust held a regular trustees meeting at Network Rail in Manchester on 18th April 2016.
Paul Hodson, the responsible Project Director kindly updated us on progress fixing the major landslip at Eden Brows. Some diagrams and pictures will be available later.
The slip is approximately 150m x 250m with some 500,000 tonnes of material (or 10 QE2 Ocean liners) which is still moving. Unlike other major slips at e.g. Harbury Cutting in Warwickshire where material is falling onto the railway, this slip is taking the railway with it and it is not possible to divert the railway away from the slip. The root cause of the slip is the saturation of embankment fill over the red sandstone bedrock. The embankment fill was placed there by the Midland Railway during the construction of the line some 142 years ago. Investigation by geotechnical engineers has shown this fill to consist of rock and earth from tunnels and cuttings along the line which was brought after there was a major slip during construction, so the Midland Railway fix has lasted 142 years before failing. The failure has a technical name of 'rotational slump' . There are many images available by Googling 'rotational slump'. The wet weather over Easter has caused further movement.
The site is very difficult and dangerous to work, due to its remote location, the slope and presence of mature trees.
The red sandstone bedrock is some 20m below the surface – the whole of this 20m x 150m x 250m section of embankment fill is on the move, sliding over the bedrock. The proposed solution will be to construct a 150m long piled retaining wall and slab to support the railway – in essence a buried viaduct. The detailed design will take until June and then heavy piling and construction will take place over the summer and early autumn, with a view to having the line open for traffic in 2017.
A network of haul roads and a construction compound are now being built so the engineers are ready to go once the design has been completed and signed off. It is planned to bring in some material by rail in order to mitigate the effect of construction traffic on local roads.
It is anticipated trains will run to and from Armathwaite in May, so allowing passengers to travel most of the length of the S&C.
It will be a multi million pound project which has been approved to proceed by Network Rail – so we’ll be getting the S&C back in good order after all this disruption."