Need Advice on Kato RSC-2 HO Pickup Etc

I acquired an Ebay Kato RSC-2, which arrived and looks very near new except someone added an NCE DA-SR decoder and thought about adding a speaker (some fiddling in the cab) but did not. The handrails and other details are still in the packaging. Anyhow, I removed the shell and lightly lubed the worm gear and motor bearings.

I ran it around and it is iffy on pickup consistency. I ran it over an alcohol wet paper towel to get the wheels nice and fresh, When doing that, I note that it is getting power from only one of the trucks. It has good pickup when one is on the track (the other on the towel) and zero pickup when the other way around, even when wiggling things.

So, I presume I have a connection issue between the truck and the common brass ribbon running along the top of the frame. I could investigate further but need to remove the truck to do so. Does this come off like a Proto 2000 truck; i.e., is that a clip atop the worm gear that gets pryed and removed, then the truck drops out. Please advise in detail as I don’t want to break anything.

I’m surprised one truck works so well providing power and the other not at all. Any advice most welcome. I’ve attached a drawing:

Thanks for any advice!

Remove the tower clip and the truck will drop away.