Hi Dave,
I guess these clips are more or a less the same as other brands clips like Bing and marklin, and cheaper Euro tin plate. As I don't bother that much on which make my trains run, I have a whole range, most of them found on flea markets and so on.
The clips just fit in a tiny slot of the opposite sleeper (the first and last sleeper are having a slot at one side and a clip on the other. Usually clips are missing and you can do fine without them. I think the clips are only handy when the track is brand new, and not much of a help when your track and clip is worn.
Only thing you can do is squeezing the tubular track with a plier, if you don't want to fix the track permanently with screws.
regards, Kieffer