ABSTRACT
In practice, the majority of railway projects do not begin with a greenfield (fresh) site. Therefore, effective and responsible human factors engineering requires a clear and justified identification of those human factors processes that are necessary as a result of system modification. The fundamental requirement for such a selective approach is to have a clear definition of the criteria that can be used to establish when a human factors process is required. For practical purposes, a working definition would be “The implementation of an appropriate human factors process is required where significant differences in roles undertaken, or where predicted levels of human performance, implementation of new or modified systems and interfaces give rise to system risk modifications.”
