Hydraulic slides are frequently used when pecker pins won't work for some reason. For example very tall slides must be pulled hydraulically because pecker pins exert too much torque on the slide gibs and may cause binding. Locks are still incorporated in the same manner as in a pecker pin slide. Limit switches tell the press whether the slides are in or out. This is a big file but cool to watch.
Shown is an example of hydraulic slides as used in the Silicon Graphics O2 top case tool.