This paper presents a general framework to assess urban rail logistics suitability via a socio-economic cost benefit analysis. Firstly, we propose an overview on the basic notions of CBA and SCBA. Secondly, we identify and present the main types of costs and benefits or railway urban logistics services and the related final delivery services using low emission road vehicles to serve customers where the rail systems cannot. Thirdly, as an example of application, we propose to assess a scenario of deployment of a freight tramway in Paris, in a possible configuration. The results show the potential of those approaches but also show that it is important to contextualize them and inform the different users about their real capacities.