Comment by toast0

Very few electric customers are served by more than one substation, that substation and the distribution wiring between the substation and the customer are going to be a SPOF, except for the few customers with access to multiple substations.

Some substations don't have redundant feeder power either, although that's more often the case where geography makes it difficult (islands/peninsulas)... But the mention of wiring on a bridge might be an indication that is a geographically difficult area of Berlin?