I suppose this might be finnicky but you could make them out of gumpaste or fondant? If they're wooden, that is and not a solid staircase. Roll out the fondant and make the railing first (either one solid -cutting out spaces in between the slats, or cutting out individual slats and 'glueing' them onto the top rail). and then making the individual steps, would have to lay them on something to dry to hold the shape, then have a strip of fondant to lay the upside down Vs on (each step) and glue that way, if that makes sense. Sorry, can't draw it as i'm not at home