@pony I didn't know they have a backup engine. Of course it makes sense, it just never occurred to me. I learned something today... Thanks.

@FailForward that's becoming increasingly anachronistic though, nowadays, it's usually a battery (with increasingly big ranges), i've been watching this and most trolleybuses being sold today have batteries, it's increasingly rare to find a "pure" one

this picture is still just a PR photo (if running on diesel/battery, you lower and tie the trolleys, obviously)