Once upon a time I found a site that shows a beautiful trolley/interurban HO layout that once appeared in a Model Railroader issue. This layout is built in various sections, one depicts the downtown, another a residential suburb, another one an industrial area and finally another a country land. I lost the address of this site. Is there someone that knows the layout and its site?
I realise it’s not precisely what you’re looking for, but http://www.blackpool-in-the-box.freeserve.co.uk/ might be worth a look too - it’s a Briti***ram layout with automated operation and working lighting effects at the trackside. They have a fair amount of information that would be equally applicable to HO trolleys.