which hitech servo is suitable

hi
i am making a system their is a rack and a pinion(Gear).a servo is mountain on side of the pion i want pinion move on the rack due to servo.plz help me which servo is best fot this purpuse .if you want i will send you a pic of my system.

Since this is a non standard application I can't say what servo is best for it. If you know roughly how much torque you will need for this setup you can compare servos and decide how much speed you need from the servo and what type of gear train material you will need (nylon, Karbonite, metal, Titanium)

thanx for responce
actually in i got this idea from a research paper.the auther use heavy duty high torque alnalog servo .but i am not understanding which servo is innstalled .i sugest HS625 . Plz see the pic

Does the author give you any specs for the servo he used?