UIC Leaflet 530-2 defines conditions that must be complied with by wagons from a running safety point of view, irrespective of their type of coupling. Running safety is taken to mean negotiating twisted track and the longitudinal compressive forces generated during braking or propelling movements. By defining the technical features of current and new wagons, the relevant safety requirements can be met when such wagons are deployed in operations. For wagons of conventional design as well as operations with the automatic buffing and draw coupler, running safety can be assessed by using a series of diagrams. For two-axle wagons equipped with screw couplers and side buffers and which have defined technical characteristics, running safety can be checked through a diagram specially designed for that purpose. Furthermore, for some two-axle bogie wagons, there are technical conditions which, to show compliance, do not require propelling tests to be carried out to justify the permissible longitudinal compressive forces. For other wagons, running safety must be demonstrated by the carrying out of propelling tests. The conditions for carrying out and analysing the propelling tests are set out in the appendices to this leaflet. Depending on the length over buffers and the bogie pivot pitch (wheelbase for two-axle wagons), it is also possible to use diagrams to establish whether there is compliance with the coupling conditions.