NR NR/L2/SIG/30097/APPJ ISSUE 3 PDF

The document covers the process for the preparation of the signal engineering design details for a Modular Signalling scheme, the bulk of which work which is carried out during GRIP Stage 5 and is carried out by the system supplier. It excludes scheme level design activities which are carried out in GRIP Stages 3 and 4. The outputs from the GRIP Stage 3 and 4 work are set out in the relevant Handbook Appendix and consist chiefly of the scheme plans and sighting forms.

The design process for the Civil, Telecommunications E&P, and Track disciplines is covered in Appendix N, Non Signalling Design.

Purpose

This specification forms a part of the Modular Signalling Handbook. It sets out the requirements for signalling design that apply to Modular Signalling systems and the required deliverables. Network Rail's process for signalling design, is set out in Company Standard NR/L2/SIG/11201, Signalling Design Production, supported by various associated standards which cover such topics as the competencies required by the staff involved in the work, the installation process and the testing and commissioning process.

For projects using the Modular Signalling system, this Handbook Appendix sets out an engineering design methodology with a level of production, verification, validation and assurance suitable for a safety critical signalling system but which achieves a cost saving compared with existing practices.

This is possible because the Modular Signalling system is designed for secondary routes with simple track layouts and operating patterns and a reduced operational functionality, compared with the full range which can be deployed on more intensively used routes.

Each scheme will be in many respects ‘more of the same' leading to an opportunity to create a more economical design process based on the reuse of already produced and checked designs.

The simple nature of Modular Signalling schemes may also make it possible to use automated tools as part of the design process. Previous and current design tools have been of limited benefit, in part due to the complex nature of traditional resignalling schemes. It is anticipated that the simple nature of the routes selected for deployment of Modular Signalling will enable design tools to be used in a more effective way, avoiding the need for at least one stage of human effort. It is recognised, however, that the work needed to achieve a suitable assurance of the tools validity may be significant by comparison with possible savings precisely because the design task is relatively straightforward.

This document follows the headings of sections 5 to 20 of NR/L2/SIG/11201 and identifies where compliance with the current standard is required and where there is scope for alternative methods to be adopted.

The design process which a supplier of Modular Signalling will use for each application of the system should be documented and approved. Each application will then require preparation of only a simple design specification to manage production of the design deliverables.