Network Rail has closed a line southeast of Manchester for a month to complete the next phase of repairs to an embankment that collapsed in April.
As part of the work, five drainage chambers will be built under the railway at New Mills.
Soil tests were carried out on site in early April and confirmed that immediate work was required to repair a slope on which tracks run.
According to Network Rail, there is a risk that 50,000 tonnes of earth could slide from the embankment into the River Goyt below if stabilisation measures are not taken.
Major repairs began in May, but since then engineers have discovered “more complex problems” with drainage.
As a result, five chambers will be created under the railway to collect excess water and channel it into the river. This will also make the railway more resilient to climate change.
A Network Rail spokesman said ENG in May that the dam sits on “lateral ground between New Mills and Marple, with a steep, large catchment above and the River Goyt beyond the top of the embankment”.
They added at the time: “The dam was constructed on a natural slope consisting of boulder clay overlying mudstones and siltstones of the Millstone Grit Group.
“The fault is believed to be a deep rotational fault within the glacial moraine and weathered bedrock. Water was a key factor in the overall stability of this dam, and the route planning team found that it deteriorated after periods of extreme weather.”
Network Rail worked with specialist geotechnical consultant and designer Coffey Geotechnics on the repair project.
Network Rail project manager Vitesh Solanki said this week: “I am sorry that the closure of the railway line will cause disruption to passengers. We have received a warm welcome from the people of New Mills and are grateful for their patience while we carry out this important work.”
A Northern spokesman added: “We would like to thank our customers for their patience while this important, safety-critical work is carried out by Network Rail. We will do everything we can to ensure customers can still get to their destination – but they should allow extra time for their journeys.”
During the closure of the railway line between Marple and Chinley, trains will be replaced by buses until 23 September.
