scope:

Introduction

This guidance document is intended to assist designers utilising Network Rail (NR) Standard Designs and Details (SDD) in schemes on the UK rail network in discharging their duties under Technical Specifications for Interoperability (TSIs) regulations.

NR Standard Designs and Details

Network Rail have undertaken the Standard Designs and Details programme to improve safety, asset reliability and increase efficiency through the provision of standardised civil engineering components for use on the national network.

They have been developed to align with Network Rail's overall business objectives; to improve reliability of the railways and reduce the funding requirements for on-going management and maintenance of the network.

The SDD have been developed with the following objectives:

• Ensuring that the designs meet Network Rail's underlying requirements. 
• That the designs are as successful as those of previous railway engineers, who built and maintained infrastructure that have given good service for approaching 150 years.

The use of the SDDs is promoted from the highest level within Network Rail. Network Rail's requirements are split between two areas; delivery and function.

Delivery Requirements

The individual SDDs have been advanced to varying stages of design (F001/002/003 as appropriate) according to their level of standardisation and have been submitted and approved. This aids the designer and NR by reducing the design development timescales and costs, minimising additional costs associated with uncertainties in detailing requirements, and streamlining the technical approval process for commonly used designs and details.

Functional Requirements

The individual SDDs have been designed to provide satisfactory performance under both normal operations and abnormal operations (through a suitable level of robustness). A further consideration has been Network Rail's requirement to reduce the volume of maintenance and management costs through the adoption of good practice. Key design drivers included predictable failure modes, no hidden details, robustness, capability to support load, acceptable deformations, geometrical flexibility, and Safe by Design principles.

Technical Specifications for Interoperability

TSIs are specifications produced by the European Rail Authority (ERA), covering the core rail system areas, which are intended to harmonize the essential requirements to ensure the interoperability of the European Union's rail systems across the Union.

As a part of the European Union the UK is legally bound to comply with these TSIs.

Interaction between SDD and TSIs

TSIs take the form of design requirements (specifications, commonly understood as standards) that railway assets and systems are required to conform to, for the purposes of harmonising the railway network across Europe.

Civil assets on the UK railway network in their built condition are required to be compliant with TSIs. This requires schemes, and SDD where a constituent part, to be compliant. The realm of TSIs can be overwhelming at first glance therefore this document aims to aid the scheme designer in their navigation through and implementation of these requirements.