This Standard describes the hydrological and hydraulic requirements (functions, performance, design constraints and risk attributes) for the design and assessment of railway infrastructure in relation to all forms of drainage and flood-prone areas.

This Standard is intended to govern public and private railways and railway drainage systems on a whole of life basis, and any other drainage related work affecting the rail corridor.

The subgrade is considered to be equally important for track performance as rail and ballast, and the main purpose of this Standard is to provide a framework that promotes consistency and efficiency in design, construction, commissioning, maintenance, monitoring and decommissioning of track drainage and waterway crossings.

This Standard is concerned primarily with the hydraulic design of surface and sub-surface drainage systems including river and floodway crossings, culverts, pipes, channels, pits and grates.