This document presents the maintenance and improvement principles of substructure and track bed layers for existing railway lines.

It provides comprehensive technical expertise and managerial knowledge with precise explanations for use.

The principal objective of the document is to expand on the content of UIC Leaflet 722 by adding a methodology for performing inspections and the usual procedures for maintenance, renewal, corrective, risk mitigation and improvement work.

The first chapters are devoted to showing the general cross-sections of conventional ballast tracks and continues by listing the requirements of a railway track and describing the potential problems that can occur in existing lines, relating to cuttings, natural slopes, embankments, platforms, track bed layers, slabs, and drainage and catchment systems.

Taking the previous ideas into account, a methodology for performing inspections is proposed based on different steps: basic and detailed in-situ inspections, and ground investigation in zones with problems. Once the inspections are complete, a comprehensive list of solutions for the corrective work is provided.

Finally, the usual procedures for maintenance, renewal, risk mitigation and improvement work are described, which complements IRS 70719 on “Earthworks and track bed layers for railway lines – Design and construction principles”.

The work was developed by the Working Group for updating UIC Leaflet 722.

Link to the IRS: Maintaining and improving earthworks and track bed layers (réf. 70722/E/1-PDFs) (uic.org)