Hi. If you are dealing with a single door rather than a pair of doors, visit http://www.fixpocketdoors.com/page2.html
Pocket doors have a trailing edge and a leading edge. Trailing edge is in the dark at all times. Leading edge (and its molding) has the finger pulls/lock assembly. The leading edge of the door is usually, but not always, outfitted with a "meeting molding" which was attached by nails. The purpose of the meeting molding is twofold. It adds width, on purpose, which can be removed when you want to move the door (sideways) into an adjacent room. Secondly, meeting moldings also usually have a "male" or convex shape that "docks" or nestles up against either...the concave/female meeting molding of any second door (of a pair) or nestles up against the "destination" jamb trim (which is either a recess/socket/concave shape) of a single pocket door opening.
Since everything about single pocket doors is ratio, spacing and proportion you are dealing with close tolerances. But in all practicality, those "close tolerances" are nothing more than the thicknesses of the applied jamb trim. The ratios and proportions are set up (or should be) so that when the leading edge arrives at the destination jamb trim "socket" or "recess", the trailing edge has not departed from the pocket.
The idea, obviously, is to have enough width to a door so that when the door arrives at the destination jamb, you can't peek past the leading edge-it is nestled into the approx 1" deep recess. (The 1" recess or "docking area" is not the same as the 6" demi-pocket mentioned in the following para.) And also the door's trailing edge doesn't exit the pocket; therefore you can't see from room to room on either edge.
Now, when something goes wrong with the operation of the door, sometimes, but not always, the door has to be removed. Therefore "fixing the door" by taking it out of the opening is nothing more than removing the jamb trim which the installers applied. Of course there's two jamb trims-first at the pocket edge (full pocket) and secondly at the destination. But the jamb trim at the destination is more complex-not only somewhat thicker but there's something else.>>> Hidden behind that "destination" jamb trim is a "demi-pocket" or "semi-pocket"
and it is usually about 6" deep (give or take.) This can give you some "wiggle room."
Now about your observation that "someone down the line" removed something...when a single door stops working easily and nobody knows how to fix it, the only "solution" is to bury it in the pocket. Of course, people could simply leave their nonfunctioning door with its edge protruding-but they usually want to "bury it." The only way to bury it is to shrink the width of the door
and cover it over (with inappropriate trim.) People who want to bury the door usually figure out that if you remove the meeting molding the door will be "less wide" and they're right. That is probably why you are noticing that your door's edge is missing something.
But nothing of the above is an answer to why your door can't be brought beyond halfway or so. Since your house is circa 1875, it is very likely not like the door on page 2 of my website.
and you will see mention of several pocket door mechanisms. Look at the "mockup" pix of parallel wood tracks. If you can feel/see parallel wood tracks and your door is grinding to a halt halfway across its travel area, then there is a simple test to determine if your parallel wood tracks are the same height. Write me with your observations and maybe we can fix your door "remotely". By the way, look at "Treating by mail" on the same website for examples of good, informative pictures. Thanks.