 It consists of an underframe, which is created by seam-welding a number of aluminium alloy extrusions, upon which bodyside panels are mounted followed by a single piece roof, again made from extruded sections.The car ends (cabs) are made from glass-reinforced plastic and steel, and are huck-bolted onto the main car bodies.Underframe components are collected in 'rafts', which are bolted into slots on the underframe extrusion.