scope:

Introduction

This Track Work Instruction covers improving the flow though a culvert. It indicates what you can do and what assistance you may need.

A culvert is defined as a construction comprising a span less than 2.0m under the railway to allow the free passage of water under the track.

A culvert is likely to be greater than 300mm diameter - less than this size can be referred to as a pipe - but in some parts of the network even pipes are referred to as culverts.

Generally culverts are marked, or given an identifying number, with records kept of inspections - normally by the structures inspection contractors.

The way they are numbered or identified varies. On some lines they are given bridge numbers, on others they may be marked with a post with the letter 'C'. Some culverts are neither numbered nor marked - they are just referred to in the records by line mileage.

See also the separate instruction:

TWI 3G048 How to inspect a culvert