I do not have the trolly set, so I can't speak to that specifically. I do have a couple United Traction trolleys and have tested them. They run fine IMO... perhaps you're used to running stuff fast, but I think trolleys, railbuses, geared locos, etc aren't made to run 'fast'. With that said, they don't run unbearably slow.
Now, to your question about alternatives. You can run the trolleys with another controller, like this one below. It has momentum and you can add a station stop, or several, between the end points. They have a version without station stops if you want that. I've purchased from them, and they ship very quickly and should arrive within 2 weeks, but probably sooner.
https://blocksignalling.co.uk/Shuttles/SAS2-BR
Now, to your question about alternatives. You can run the trolleys with another controller, like this one below. It has momentum and you can add a station stop, or several, between the end points. They have a version without station stops if you want that. I've purchased from them, and they ship very quickly and should arrive within 2 weeks, but probably sooner.
https://blocksignalling.co.uk/Shuttles/SAS2-BR