This study aims to improve the RAMSHE LCM procedure at ProRail. This procedure expresses the performance of rail infrastructure in terms of Reliability, Availability, Maintainability, Health, Safety, Environment and Life Cycle Costs. When executed right it can help estimate the future performance and costs of new rail infrastructure. Currently, employees have too little knowledge about the procedure and the use rate is too low. Our research follows a lean approach on process improvement by using the DMAIC cycle to structure the research. We first define the situation by performing a stakeholder analysis, measure the current performance using a survey, analyze the results and come up with improvements and control measures to ensure sustainable improvement. The result is an improvement plan which decreases the waste in the procedure and increases the use rate.