In message
,
77002 writes

Often wondered if there is an application for a streetcar/tram or
electric/trolly bus that runs under wires where practical, but
utilizes batteries for stretches where wires are not practical, or
unsightly.

Trollybus route 90 in Rome has been operating on such a system for the
last 6 years (more recently joined by route 90D). Batteries are
recharged while running on the wired sections, and the changeover is
fairly well automated:

http://www.youtube.com/watch?v=pTJYsIdZlTg
--
Paul Terry