Quality "Ring" type connectors that will fit a Lionel 6-14112 lighted lockon correctly?

I get most of my ring terminals at either NAPA or at a marine supply store. Once you crimp them on the wire, solder them too. This will ensure a good solid connection. I do this on all of my electrical connections when I restore cars. You should be able to get the correct size ring you need.

Thanks for the tips.  A NAPA store is just down the street. It looks like the stud on the lockon  is about 1/8 inch wide

There's multiple stud sizes in addition to multiple wire sizes. Both sides of the terminal need to be properly sized. So whether you use "cheap chinese" or "fine [insert other country here]" terminals, if they're the wrong size, it'll make no difference. 

Crimp with the correct tool and use the correct size for the stud you have. The locking spade connectors work well too and wont back off. 

OK, thanks for the help. 

Question:  as you may know, this particular lockon has a green light that glows when power is being supplied to the track.   If this light goes out when I'm experiencing my stop/start problems, does this mean that the wires connected to the lockon themselves may be the source of the erratic behavior or will it go out even if there's a short or other connectivity problem anywhere on the track layout?