TN0304 Iss 1

This technical note has been issued to help the industry manage the sighting of colour light junction signals. This document is responding to the RAIB report 10/2024: Overspeed at Spital Junction, Peterborough recommendation to review the standards specifying the relative brightness of main aspects and junction indicators on signals to understand the effects on conspicuity of the complete signal.

RSSB is inviting feedback on the content of this technical note and the standards specifying the relative brightness of main aspects and junction indicators on signals to understand the effects on conspicuity of the complete signal up to the maximum distance at which a signal is required to be readable.  Any feedback received by RSSB will be used to inform the next updates of standards GKRT0057 Lineside Signal and Indicator Product Design and Assessment Requirements and RIS-0737-CCS Signal Sighting Assessment Requirements.

The lineside signalling system provides drivers with some of the information they need to safely control trains, including information of: i) The distance to go; ii) The direction the train will take at each junction; and iii) Permissible speed changes.

Where trains are operated using the lineside signalling system, drivers obtain this information from signal aspects, indications and lineside operational signs.

The infrastructure manager (IM) provides and maintains the lineside signalling system so that drivers can reliably obtain the information with enough time to act on it. Railway undertakings (RUs) ensure that drivers can reliably read and interpret signal aspects, indications and signs, and act on the information provided.

Risk assessment is used to confirm that the lineside signalling system is safely integrated with train operations before a planned change is put into use.