Guess propulsion type by its noise

[Stanley514]

Could you define what propulsion type this one vehicle uses by noise it makes?

 

[AlephZero]

Judging by the poles along the route, (and some of the other videos listed on the youtube page) I guess it's a http://en.wikipedia.org/wiki/Trolleybus

There were in use in a town about 30 miles from where I lived in the UK, back in the 1950s and 60s. They were remarkably noisy, for electric powered vehicles.