>>1429767The trolleybus is using a different set of wires than the tram, although the electrical system is shared. That's because the tram wire is set up for pantographs and not trolleypoles, so no wire frogs and not hung straight. Only trams with trolleypoles can share wire with trolleybuses (they do in San Francisco), because the pantograph could too easily come in contact with the negative wire which would cause a short circuit.