Punt da Suransuns, Via mala
Ing. Jürg Conzett, Chur
Here, one can see how the structure of the bridge functions (my interpretation anyway):
The supporting flat steel members were pulled back and put under tension (see base-plates for winches in foreground?), were then loaded with the stone slabs (between which there is a thin stainless-steel sheet), which were then wedged together, forming a compression-plane (one can see the wedges jutting out above the 'eyelets'), thus keeping the bridge from swaying.
Voila. (am I right?)
The railing has nothing to do with the support of the bridge.
Check out the 'set' on the right for more pictures of this one.