In line with the trend of spread of Lean Construction concepts in the recent past, Lean construction philosophy was introduced in a large industrial project of a leading organisation about two years back. The drive by the top management, augmented by efforts of the Lean champions in the project team, helped the project team to transition from the conventional project delivery method to the Lean Construction method. The present study looks at the developments in Lean implementation in the Project over time, based on observations on such dynamics and understanding the strategies which might help to mainstream Lean philosophy introduction in other similar organisations and construction projects. A detailed case study based approach was adopted to this end. The mentoring coach closely observed the behavioural developments of the Project team over time. Data for analysis included primary observations by the mentoring coach, minutes of the various meetings of the project team under study and one-on-one interactions with various team members. The analysis gave some significant insights on how to continue the initial momentum gained towards sustained Lean implementation on construction projects and in organisations.