Railway-control systems must cope with strict dependability requirements. Typically, a product or installation is composed by several applications, different operating systems, and a number of hardware pieces. The range of combinations is large and thus the range of products in the family. In order to keep this figure small, handle the development process efficiently (unavoidably delayed by the validation efforts required) and to isolate software and hardware elements, Alcatel Transport Automation Systems (TAS) took a strategic decision: to choose an operating system able to hide hardware variability, and provided by a third party. This paper describes the concept of product family used by Alcatel TAS, organized around an operational platform for applications in the product line, reports the experience carried out in Alcatel Spain, in porting existing railway control applications to the Alcatel TAS Platform (an operating system developed by Alcatel) and discusses some advantages of this approach.