This study aims to create a model to use internal measures for service quality evaluation. Using internal measures provides continuous (daily) service quality measurement and faster improvement efforts allocation, we find them more applicable and useful for service quality measurement. This paper demonstrates that using SERVQUAL lonely cannot be efficient, so we need some new improvements. This study proposes a model that can use internal measures for continuous and more effective evaluation. The quality function development method is used for translating customer expectation to internal measures. SERVQUAL dimensions or statements are employed as customer expectation that they are perceived by SERVQUAL questionnaire. Moreover, this paper tries to optimise this translation by a mixed integer linear programming mathematical model. This model can optimise the service quality translation to enrich the internal evaluation with customer opinions. Finally, the proposed model is employed for optimising the evaluation of the train’s internal service quality.