AS this is the second incarnation of this problem, I'll add a bit more to the answer I gave in the posted link. (I know that DavidD's problem is solved, but to prevent my fogetting to post it next fall, I'll add it to the data base)
In my other (linked to) post I crypticly asked whether a SWCG was involved - last year I noticed that while some of the older pools has 'stubborn' rails,(ladders)- almost all the new pools with SWCGs had PITA rails. After finally figuring out the correlation between SWCGs and hard to remove rails, I posted in the SWG forum about my observation - sure enough, the knowledgable folks here answered -
A summery (from memory):
1) I wasn't halucinating (I always like to be told that, I can never be sure )
2) Salt water introduced to 2 disparate metals WILL increase the oxidation (there was a white 'slime', which I believe was oxidised aluminum from the anchor cups)
3) Try paint or tape to keep the metals separate
4) Try a 'sacrificial annode' (zink, I believe) to 'rot' before the cups or rails
5) Use plastic anchor cups (not an option, my boss refuses to even think about using them)
- I then posted a follow-up ? - "could I caulk the joint where cup and rail meet to keep the salt water out of them?"-
The answer was 'YES' - no salt water in the cups = no 'undue' oxidation.

Well, when I suggested the caulking to the boss, he promptly ignored it and kept ignoring it all year (what does he care if I have to herniate myself to remove the rails? - all he wants to know if if the pool is closed and 'can we bill them?'). So I've added another weapon to my 'rail removing arsenal' - water (our old friend DHMO ). When a rail gets stubborn (whether from SWCG or grit and debris) the first thing I do is pour some water onto the cup and work the rail as much as I can, to get the water into where it needs to be to do it's job, if it stays stubborn, I walk away and do something else for a few minutes, then come back and try again. It may take a few repititions and PATIENCE, but usually works. Water is aka the 'universal solvent' and can work wonders on all sorts of things which need a little 'lubing'.

As said before, Dave - I'm glad you were able to resolve your rail issues!