I think they’re invented quite a while ago, like the around the year 1900 or so.
Well, first trolleybus was created in 1881. But if we talk about more or less modern trolleybuses with rod pantograph – they appeared in 1909. 🙂
I know what now trolleybuses not very popular in Europe and USA, but it would be very nice if we could see trolleybuses in TF. I am ready to provide any assistance if required. 😀