Improved Earthworks Drainage for Safer Reliable Railways

Recent study of NR earthworks failures has confirmed a statistically significant link between poor drainage condition and incidents of failure in certain geological conditions. However, with 10,000km of earthworks on the network a prioritisation approach is required to determine where and when to intervene to improve earthwork drainage condition. This project will develop models of the precipitation, evapotranspiration, infiltration, runoff system for earthworks and their associated vegetation and use this model to develop prioritisation guidelines for identified vulnerable asset groups. The model will include examination of the balance between improved earthwork stability linked to vegetation and the potential for leaves and roots and clog drainage materials and disrupt pipes. The model will also couple to a holistic view of the drainage network to consider the impact of improved earthwork drainage on the overall drainage system including downstream capacity.

The aim of the project is understand the integrated slope-vegetation-drainage system for railway earthworks to permit prioritisation of drainage renewals and maintenance. Specific objectives are to:-
(i) Develop a models for interactions between climate, slopes, drainage and vegetation to enable identification of groups of vulnerable earthworks which would most benefit from drainage renewals and/or planned maintenance.
(ii) Understand the trade-offs between the positive and negative impacts of vegetation on the NR drainage asset leading to improved vegetation management strategies.
(iii) Understand the impact of improved earthwork drainage capacity on the overall drainage system, especially downstream capacity and consequences.


The potential benefits of the project include
(i) Increased resilience of earthworks resulting in improved safety with fewer failures, reduced earthworks renewal costs and increased customer satisfaction through improved reliability and reduction in delay minutes.
(ii) Better prioritisation of drainage renewals & maintenance budgets.
(iii) Better integration between the provision and maintenance of drainage and earthworks assets, including vegetation management strategies that work for both types of assets.

The project outputs will include, system models, identified vulnerable earthwork groups, improved renewals prioritisation guidelines and vegetation management strategies.