Regulating rail treatment

[A440A@aol.com]

Greetings, 
> "Is there a better treatment or technique for
>freeing up these frozen screws?"

Heat, and a fair amount of it.  You don't want to char the wood but 250-300
degrees on the screw will usually dry out  and shrink the wood around the
threads. 
 It is also advisable to turn the overly tight screws back and forth, just a
little at a time, until there is increasing movement.  Then you may succeed in
getting it to turn a complete revolution.
 Regards, 
Ed Foote