A picture is worth a thousand words. A diagram please? Show us some of your ideas. That would help. You can do that without disclosing proprietary information.
"In rack and pinion, rack alone moves so, it is preferred."
So, you're moving the rack? Why? It will stick out at each end of travel!
If the moving load is already 10 tons, I don't see how adding a motor and gearbox to drive a pinion or sprocket will add noticeably to the moving weight.
Your initial question was "which is more efficient in operation and cost, worm and rack or telescoping cylinder?" In my opinion, neither of them are desirable. A worm and rack is the picture of wear and inefficiency. A telescoping cylinder is the picture of costly. And a horizontal one is a maintenance headache! There are so many other ways to move a load.
And now you tell us its only once a year! That would have been nice to know. If its only once a year, why do you even care about efficiency? Why power it at all? Get a hand crank winch, call it a day, and move on to the next project.
I don't mean to be rude but I have to ask - have you designed linear motion systems before? If so, you know what information we need to help you. If you haven't that's ok too. We all have to start somewhere. Get some personal advice from an experienced mentor where you work.