Project alliancing (PA) as an interactive contracting mechanism is arguably an archetype of modern-day contracting. Well-designed PA emphasises the notion of shared goals and objectives, including detailed understanding and recognition of risks and reward while recognising specialist contribution by parties. However, PA has significant influence on organisational culture and cultural theory, hence reflecting the effect of culture on performance. This research study aims to determine the influence of PA on organisational culture and project performance, using the UK rail industry as a case study. A quantitative methodological approach was employed with quantitative data collection through questionnaires from 56 respondents (25 clients’ and 31 contractors’ all working in the rail industry), on a case study of an on-going alliancing project. The questionnaire results were analysed using the mode as the central tendency approach and focusing on the values that occurred most. The results from the research validated findings from the reviews while highlighting other fundamental factors underpinning the success(es) of PA in project management. This study is beneficial in improving the fragmented nature of the construction industry while positioning team building and collaborative working in the core of construction project management.