Initialy they decided not to use power lines for trams due to them looking bad "any way they tried"
I think they decided on that due to the diferent trams having other power connectors, and they would not connect.
For some reason the 3 trolly busses also have diferent poles on the roof, all of them not connecting to the lines.
While in reality the poles would easely be bended to fit.
For trams however the double deckers would be impossible to fit in under the wires...