scope:

This business process applies on all Network Rail managed infrastructure and all signal assets reading onto Network Rail managed infrastructure.

It applies:

• to all new signal assets and alterations that impact the signal sighting of a signal asset;

• when assessing signal sighting following Category 'A' Signal Passed at Danger (SPAD);

• to signal assets that require an assessment of signal sighting by mutual consent of the affected stakeholders;

It applies to Infrastructure managers, Operations Managers, Station operators and individuals introducing changes to or impacting signalling assets.

This business process does not apply to Signal Technicians Signal tasks for alignment and visibility of signals. This process is detailed in NR/L3/SIG/10663.

The full requirements for the testing and commissioning of signal assets are not included in the scope of this business process. The testing and commissioning requirements (NR/L2/SIG/30014) include a compliance check of the installed signal asset against the approved signal sighting assessment record.

Purpose

This business process describes the process to assess signal sighting of proposed or applied signalling assets to be read and understood by train drivers and staff influencing train movements.

The output of the assessment is a record of the considerations and judgements taken to define the recommendations of reasonable actions to optimise the interface between infrastructure and train driver. The record of assessment enables management of the risks associated with train operations controlled by new and existing signal assets.