like lava the slag glow in the dark when the blast funance is working at night. The Walthers slag and steel waggons are equiped with a bulbs at the bottom and a disk of clear plastic painted with various red's on the top. The channels for raw iron and slag channels at walters blast furnance are filled with electroluminicent cords embedded in "water" to simulate the material flow. The action take care on my European stile H&HRR (Hamburg & Heidelberg Railroad)