As a binary question:
Does the road width on a plat of 60' override the found monumentation on the ground showing 50'?
Original monuments are king, they hold over paper notations. There are rare exceptions, but those are rare. Yet here we have presumably secondary monuments. Can those override the plat distance?
Yes.
They can be set from evidence of the original subdivision, in the PLSS those are called obliterated monuments and the same principal exists in subdivisions.
So, the answer is unclear.
Now we find out that the plat is not the plat but rather a copy of the plat, and not actually a copy of the plat but integrated into a larger map of the city with many subdivisions welded together.
Those maps are not unheard-of, I've got one for my city and its helpful with interesting notations of found monuments and 60' streets found to be anywhere from 55' to 67' wide. It's an early form of GIS and it's way better for location information than the present day computer GIS. But, like the computer GIS It has errors. Many towns have redrafts of original plat maps, but always use them with suspicion. Looking at the original and the replat will usually reveal errors making the redraft.
I'm really moving my opinion (without being on the ground or an ability to research) towards the monumentation.
A pre 1860 plat that's lost or destroyed and then sometime in the past by someone recreated into a larger map doesn't inspire confidence in the paper information.
The Right-of-Way matters, because that dictates the Point-of-Beginning.
Who told you that? What matters in a old subdivision is where the boundary lines have been established. A great place to start in an old subdivision is finding harmony comparing the map to the location of the oldest infrastructure in a particular block. Also the fact irons don't agree from block to block is not uncommon in old subdivisions and is for the most part irrelevant to the location of established (legal) boundaries in another block. There have been many surveys disregarded by the court including in CA that attempted to fix everything by starting at some distant POB and laying out the "official" map off of it.
Knerr v. Mauldin comes to mind.
How binary circuits work, at least in computers: The answer flips back and forth unpredictably between 0 and 1 until the clock cycle runs out, and whatever the signal is when the clock says "time's up" is the answer.
"Original monuments are king, they hold over paper notations."
This statement is overly broad. Called for original monuments occupy the summit of the hierarchy of calls. Other monuments, even those first set, are evidence but must be proven. Merely setting monuments does not give them dignity. Owners must act in reliance upon them for them to become binding. For that to happen they must first be aware that they exist. This must be proven, not assumed.
We have here a story with a lot of holes. We have a compilation map showing width which may or may not be correct. We have monuments which were set we know not when, or by whom, and under what circumstances.
We have mention of Points of Beginning. P.O.B. would not be an issue if the right of way in question was established by plat. You do not describe platted property by reference to a P.O.B. Although not expressly stated the monuments do not seem to have been called for in the descriptions - if they had been their status would not be in question. The described depth of the lots, measured in from defined rear lines on both sides, may offer insight. The POB has no more importance than any other described corner. Nevertheless we may not have any comprehensive survey of the right of way, nor any definitive establishment document, nor any call for monuments in the deeds.
We need to look for a statute or local ordinance applicable at the time of establishment that dictates the width of newly opened rights of way. Even a pattern of local practice would be of interest. If right of way improvements fit neatly into a 60 foot corridor, that would make the width 60 feet by estoppel. If they fit a 50 foot width that argues in favor of that number. I think that courts would lean to the minimum that fills the public's needs.
In short, the monuments are evidence. Maybe even strong evidence. But I'll need to know a lot more about the whole setup before I declare them definitive. If I owned property abutting this RW I'd assume the wider width and act accordingly for the time being.
Curious, you can't provide vague information and expect clear answers. If you can't provide all of the information on this public forum, then you need to establish a private connection. I'm unsure why you can't do this with the 2 surveyors you have already hired. Ultimately the answer to your questions will reside with a surveyor and if not there, then the courts. But you have to provide all of the information to get fully informed answers.
The City may have original field books containing information about the R. O. W. rods. I'd look through those records and any others that may come to your aid. Are there any recorded documents concerning a R. O. W. alteration? So many questions, and the only way to get to the bottom.
Interesting... So, what determines Point-of-beginning? Would the map, that was drawn before the lot was sectioned off, then determine the Point-of-beginning? If so, then the row might vary, changing the actual lot size, more or less on the side of the road, but not on the other 3 sides - they would be determined by the map?
I have been to the county court house, through nearly every minute book in city hall, and contacted the state to see if they had old maps/surveys. Whereas I can show that the city council would be who would determine any change in Row back to the mid-1800's, there was never a vote to change the ROW on this particular street.
The questions you're asking are highly dependent on evidence and jurisdiction. We can all give a guess, but you will not get a reliable answer here. That isn't because we don't know what we're doing, we simply don't know the facts.
You mentioned an 'official city map'. It has become obvious this map is not the creation document for the road. That document (and the statutes in place at creation) will have a direct bearing on what prevails as far as the road width and location. I lean toward the actions of the owners as a whole. If the location and width at creation is in doubt, what was done at that time (and since) should best tell the story.
Even if that is correct, it may not help determine where the POB lies. I didn't see anything telling me exactly what this POB related to, but I have my suspicions. It is not uncommon for realtors, lawyers, and just plain neighbors to write metes and bounds descriptions of portions of lots. These descriptions often have land mines buried in the language. Decades after the parcel is sold, an ambiguity is discovered. The surveyors show up, and peace evaporates.
This may or may not be your situation, but my advice is to read what Norm said above. The technical location of that POB is far less important than what has been done to establish the boundaries. Even if there is no evidence along the lines, you should be looking for the POB as understood by the parties at the time of parcel creation. The uncertain technical POB of today that surveyors can't agree on probably won't help you...