When seeking to enhance reuse, industrial enterprises delivering complex electro-mechanical products to large global customers face various technical challenges in their engineering practice. Many challenges are due to the many-faceted and rich variability that naturally arises in such a context. We focus our attention on the requirements engineering process. This paper presents the results from a case study investigating reuse potential by analyzing legacy use cases and scenarios data for six selected railway vehicle products for customers in three product segments and on two main markets. Through our analysis, fifteen scenario clusters were identified, covering 74% of all scenarios in the products. We also found a significant overlap between products in 13 of the clusters and a considerable variation in the degrees of overlap in the clusters. We initially anticipated that this overlap would align with the product segments, but our results suggest otherwise.