ISU, the abbreviation of “Innovative Semi-Trailer Handling Unit” in German (Innovativer Sattelauflieger Umschlag), is the Rail Cargo patented loading/unloading system of non-cranable semi-trailers to/from pocket wagons.
Last years, railway operators faced with increasing demand of Turkish truck companies for semi-trailer trains from Trieste. Those started with company trains at the beginning, where an investment for cranable semi-trailers is prerequisite.
Then Rail Cargo introduced the ISU system, which enables the handling of standard (non-cranable) semi-trailers onto pocket wagons.. Thus, regular semi-trailer train services, which are not dedicated to companies, became available.
ISU system consists of wheel grippers (attached to wheel sets) and beam (attached to king pin), which allows non-cranable semi-trailers to be lifted by reach stacker using a cross-beam, and put onto a pocket wagon. The handling of one semi-trailer lasts less than 10 minutes.
Since this system needs neither special semi-trailers nor wagons nor terminals, ISU system soon became widely used in Trieste. Today, 10 ISU-supported semi-trailer trains depart every week from Trieste.
Currently used routes have a loading intermodal gauge of P/C 400. Thus the whole range of 3-axle semi-trailer to mega-trailers with a width up to 2.6 m and height of up to 4 m can be transported by these trains. ISU system accepts semi-trailers with tires with a diameter between 850 mm and 1150 mm.