The Computer And Radio Aided Train control system (CARAT) is based on the radio communication between an on-board control system and a ground control system unlike other train control systems that rely on track circuits. To realize a large-scale system based on a new principle such as CARAT, it is important to analyze safety in a systematic manner at an early stage, and identify most important factors for CARAT. The authors have selected hazards specific to CARAT, identified their causes by applying Fault Tree Analysis, and allocated safety requirements to such hazards. This paper describes these safety analyses and safety requirements for CARAT.