This paper presents the experiences from applying hazard and operability analysis (HAZOP) as support for establishing the safety requirements specification of a new safety-related railway application. The new railway application is a software based system for securing work areas, meaning it prevents railway traffic in areas along the track allocated to maintenance. The experiences are collected within the Safety Assessment Framework for Efficient Transport (SafeT) project managed by Bane NOR. Bane NOR is the government agency that owns, operates and develops the Norwegian railway infrastructure. The objective of the SafeT framework is to offer a systematic, reusable way for creating system wide conceptual design models and based on them, creating a common risk model, which in turn will facilitate safety assessment, establishing the requirements specification, and safety demonstration of the system under consideration. The experience collected on applying HAZOP is done through two workshops with different formats on the documentation. The objective was to collect guidance on how HAZOP can be supported in the SafeT framework.