NR TPWS/TI/014 ISSUE 7 PDF

This Technical Instruction:

shall be read in conjunction with the requirements of RT/E/S/10133, RT/E/S/10138 and RT/E/S/10175. This instruction supplements/amends the requirements of these standards, and will be incorporated into the relevant standards in due course.

requires TPWS to be considered only for the following categories of PSR that meet the requirements of the Regulations, including 'cascaded' PSRs meeting the criteria:

plain line curve-related PSRs.

PSRs through diverging junctions without speed control through signalling arrangements, i.e. without Approach Released signalling controls.

PSRs through converging junctions.

PSRs on the approach to vehicular level crossings.

Approaches to terminal platforms.

PSRs in place due to reduced signal spacing or reduced overlaps.

PSRs in place for the condition of asset where there is a significant risk of derailment through a single overspeeding event.

Refer to Appendix C for the TAMAR database PSR categories. Appendix A supplements the text within this Technical Instruction with a flowchart for PSR selection and Appendix D provides guidance on the selection criteria.

defines the general requirements and design rules to enable the Overspeed Sensor System (OSS) loops to be positioned appropriately, and the OSS Set Speed to be determined. Appendix B supplements the text with a flowchart.

This Technical Instruction does NOT apply to:

Emergency Speed Restrictions (ESR) or Temporary Speed Restrictions (TSR).

Enhanced Permissible Speeds (EPS) for tilting trains, which will be protected using Tilt Authorisation & Speed Supervision (TASS).