This presentation on the Absolutely Safe Train Positioning roadmap for the European FP2-R2DATO project comprises two main work packages: Work Package 21, which focuses on user needs and the specification of ASTP system requirements, and Work Package 22, which focuses on demonstrators, the definition of a common architecture, the validation process, and RAMS activities. Work Packages impacted by ASTP include WP43, WP44/45 and WP34/35. The operational analysis (WP21) states that the ASTP should provide an accurate estimated position with a specific confidence interval when the train stops at a station. Regarding the design and architecture (WP22), a set of sensors is proposed to meet the requirements, with the possibility to create exported constraints and to propose a model based on sensor specificity and user needs.