The creation of a digital twin of rail infrastructure assets places greater emphasis on requirements engineering, model-based delivery methods, and digital information management to support the creation of both physical and virtual deliverables. However, requirements engineering capabilities are latent in comparison to complex discrete manufacturing. In this paper, we explore requirements engineering practices in Australian rail infrastructure projects creating digital twins for asset management and operations. An investigation of the challenges encountered by project teams during the development of asset information requirements for physical and digital deliverables was conducted using an in-depth literature review together with semi-structured interviews with rail project delivery teams. Challenges to the maturity of requirements engineering were categorised according to their main characteristics. The process, technology and supply chain issues identified provide empirical evidence of the pain points faced by delivery teams in developing asset information requirements in support of the creation of a digital twin. Findings serve as a starting point for further research into the development of requirements engineering methods distinguished by systems-based approaches.