Define several load cases to create a moving load. Each load case should correspond to a certain position of the moving load in the structure.
You can easily generate the load cases from the load positions on members in the add-on modules RF‑MOVE (for RFEM 5) and RSMOVE (for RSTAB 8). Using RF-MOVE Surfaces, it is also possible to generate load cases from moving loads on surfaces for RFEM 5 (see the image).