To promote the permanent preservation of railway lines, engines, rolling stock and equipment and items of general railway interest of actual or potential historic or scientific importance and educative value, and to exhibit to members of the public interested in engines owned by the association any engines, rolling stock, equipment and items as aforesaid by means of temporary or permanent exhibitions and to demonstrate and assist in demonstrating to such persons the workings and operation of any such engines, rolling stock and items by means of static or mobile displays.