The "Road semi-trailer on rail bogies" system of rail-road combined transport consists of a series of road semi-trailer units coupled together to form an articulated set of rail vehicles. Each semi-trailer has its own rail-bogie adaptater equipment enabling it to run either in road mode, when coupled to a tractor unit, or in rail mode as part of a dedicated trainset. In the latter case, the road undercarriage remains in position beneath the semi-trailer and is retracted by means of a technical device. This document covers the various aspects concerned with the rail operation of this system of transport. It describes in particular the technical characteristics of bogies and semi-trailers, operations for the formation of rafts of wagons and on-line running and shunting conditions. The standard technical characteristics of the different systems are given in UIC Leaflet 597 "Rail-road combined transport systems: semi-trailers on bogies".