The maintenance of rail bogie frames, which are motorised, is carried out by completely dismantling the frame, which must be sandblasted and painted. These operations are carried out in a facility that minimises manual handling of the frame, which weighs around 3000 kg. The completely free frame is positioned horizontally with the help of an overhead crane on a hydraulic machine that automatically rotates the frame by 90° degrees to hook it in suspension on a two-rail conveyor, which is dedicated to transporting the frame first to a sandblasting tunnel and then to a paint booth. Here, after the paint has been applied, curing is carried out in the booth, at the end the frame is taken out of the booth and the hydrauic lift picks up the finished frame from the conveyor and places it horizontally available to be picked up by the overhead crane and then positioned on the assembly line. Next to this plant there is also a further plant for washing and painting the trolley motors.