ISO/TR 21245-2:2016 aims to identify basic conditions of rail projects, which are essential input for the design of rail systems. This document does not interfere with existing national and local laws, legal requirements and regulations. It considers only the "planning stage" of rail projects and does not deal with the "execution stage". Any type of rail projects is intended to be dealt with, such as building a new line, retrofitting or upgrading of existing lines and change of operation or maintenance.
In ISO/TR 21245-2:2016, conditions are dealt with as premises or constraints, which can be difficult to adjust or change by stakeholders concerned in the project.