Without a picture or something, I am not sure what the problem is. I agree with a bed that old, keeping it in a pristine condition is worth the trouble. I would try to glue and clamp the split with a good cement to fix that problem. Then how about using a ‘Locking safety bed rail bracket’, such as the one by Rockler. Go to their website, http://www.rockler.com and search for item number 32077. It might solve the problem. HTH
Let us know how it works out.