I recently bought quite a few used O22 Switches. All of them, except for one, have this small flat section of rail in the middle, which appears to be a snap-in piece. One of them does not have this rail. It is missing, and underneath it is just the black plastic with a hole at each end where the rail piece attaches. BUT, the switch with the piece missing works perfectly. All of my engines glide through it with no electrical issues, and no derailings ever occur.
So, what is the purpose of this small flat rail please? Does it carry current? Is it just for show?
Thanks for all advice.