scope:

This standard applies to all Network Rail owned or managed, Shared and Outside Party Earthworks and other structures that have been assigned to Structure Category D. In this standard the term 'Earthwork' means any type or form of construction that has been assigned to Structure Category D: guidance on assigning a structure to a Structure Category is provided in Appendix A.

The relevant requirements of 6 to 8 shall be applied to;

1 Network Rail owned or managed1 Earthworks equal to or greater than 3 metres high.

2 Network Rail owned or managed¹ Earthworks (irrespective of their height) that have a history of instability, and/or are perceived to be at risk of flooding or water action (see 8.3), and/or whose Failure could pose an unacceptable risk to the safe operation or performance of rail infrastructure.

3 Outside Party Earthworks (irrespective of their height) whose Failure could pose an unacceptable risk to the safe operation or performance of rail infrastructure.

4 Approach Embankments to an overline Bridge that are equal to or greater than 3 metres high, except those owned by a Highway Authority, Roads Authority, or other equally competent authority.

The requirements of 6 to 8 need not be applied to Earthworks that do not meet any of the above criteria.

The height of a Cutting or Natural Slope shall be taken to be the difference in level of its crest and the lowest level of the cess (or invert of an adjoining open ditch. The height of an Embankment shall be taken to be the difference in level of its toe (or invert of an adjoining open ditch) and the top of a sleeper.

Other Earthworks shall include;

1 nailed or reinforced soil slopes/walls whose face angle is less than 70 degrees to the horizontal,

but shall not include

2 Coastal, Estuarine and River Defences.

This standard does not apply to the track support system, which includes the formation, capping layers, blanketing, ballast and any geosynthetics that are integral with the support system.

This standard does not define the organisational or commercial responsibilities for delivering the requirements of this standard.

Purpose

The purpose of this standard is to define the requirements for managing existing Earthworks, and other structures assigned to Structure Category D in accordance with NR/L1/CIV/032: Managing existing structures, so that when meeting these requirements there would be no unacceptable risk to the safe operation or performance of rail infrastructure.

This standard contains requirements supplementary to those given in NR/L1/CIV/032: Managing existing structures.