The Australian Standard AS 7631:2015 Railway Infrastructure – Sighting; provides a framework to assess the optimal sighting arrangements in order to minimise risks as a consequence of poor sighting on the railway network.The documentation may be used to facilitate the optimisation of sighting and perception-reaction which are considered important safety factors in the mitigation of railway safety risks associated with: - (a) the occurrence of an exceedance of authority from incorrectly placed signs- (b) the occurrence of reading the incorrect sign, for example read-through and read-across errors- (c)railway and contract personnel working in the rail corridor- (d) authorised visitors to the corridor- (e) machinery and plant being used on the corridor.This Standard covers rail networks as classified in AS 7630 Railway Infrastructure - Track Classification.This Standard is not specifically intended to cover urban on-street tramway or light rail networks, cane railways, or heritage railways operating on private reservation, but items from this Standard may be applied to such systems as deemed appropriate by the relevant Rail Infrastructure Manager.This Standard provides a number of environmental, physical and human factor considerations which will assist the Rail Infrastructure Manager in the understanding of sighting processing, constraints and requirements. This Standard aims to provide a sound framework for the development and implementation of optimal sighting arrangements for all stimuli on the railway where it is critical that a person/s shall perceive, interpret and act upon a stimulus in a safe and controlled manner.