[frgewut]

There are also "partly electrified" possibility e.g. only 10% of track electrified (stations for example). Trains can recharge batteries or supercapacitators there from wire. There already are such existing light rail lines.

[1] https://en.wikipedia.org/wiki/Battery_electric_multiple_unit

[jakecopp]

Sydney is doing this for a new light rail line to eliminate overhead wires from the CBD.