First-Timer Foiled: Some Questions for the Pros

[+pgrig]

This benchmark (or monument?) hunting doesn't look so hard, I thought. After all, they practically give you the position in that datasheet thingy, and all you have to do is take out your new GPSr, tromp around a bit, snap a picture of your prize, come home, and thaw out-- right? Well, not exactly.....

 

And I was even on the verge of benchmark-hunting fame and glory. My target, the closest listed BM to my front door, had even been left for me alone to re-discover (it's "not yet logged").

 

OK. I'm a sadder but wiser newbie now. The "stone building" referred to in my description had been demolished. [i was able to find some foundation traces, and I actually do remember what I think it looked like, some 20 years ago. Unfortunately, the "house" (and the parkway beyond it) is not visible from the tracks, separated by a 20 ft. tall embankment about 20' from the tracks.] The direction "south" in the description was apparently not a bearing, but a general orientation, since heading south from the clearly visible RR milepost B7 cited there put me way inside (not outside) of the RR curve. My scaled coordinates seemed to place me way off, according to my GPSr (even adjusted for the right datum).

 

I scratched my head wondering if I had missed the definition of a new surveyor's unit of distance--the "rail"--which was key here. Perhaps a "rail" was related to a "chain" or a "rod", but a Google search was fruitless. [Only after I got home, and a new 8" of snow had fallen on my objective, did it occur to me that this was the linear length of a section of track. When the snow melts again, this may help. ]

 

It was nice to have a telephone pole referenced. Trouble was that the pole I thought it could have been looked younger than 40+ years, and there were several other candidates to choose from. [Deep sigh.]

 

So what now? Is there any way I can get something more specific? Contact the Mass. GS who originally placed this marker? Seek more info. from the NGS, which says it recovered this marker in 1965? Train myself as a surveyor and hire a rod man so that I know how to do leveling and distance measurement to get over these pesky banks? Order a couple of chocolate benchmarks so I can leave them as an offering to the Spirits of Benchmarking in my quad?

[+Black Dog Trackers]

pgrig -

 

Interesting benchmark hunting challenge!

Well, let's see, I'm sure you know that the scaled coordinates can be off by a couple hundred feet. Those directions they put in the descriptions are often quite crude - they only use an 8-point compass notation and I've seen many (most) that are hardly close even at that level. If you do a search in the forum for "rail", you will see that the rail thing has come up many times. Unfortunately there are 2 or 3 different distances. Also, unfortunately, the track there has probably been replaced continuous rail by this time so you won't know which it was. Here is the rail entry in holoscene's benchmark hunting wiki.

 

The worst part of this whole enterprise is the statement at the end of the description: THAT IS 4 INCHES UNDERGROUND.

 

Good luck !

 

Edit: Searching for "rails" or "rails+length" is better, I just found.

Edited January 15, 2008 by Black Dog Trackers

[Papa-Bear-NYC]

You picked a good one. Lots and lots of detail in the description:

 

ALONG THE BOSTON AND MAINE RAILROAD ABOUT 0.5

MILE SOUTH OF THE WEDGEMERE STATION, 1.3 MILES NORTHWEST OF THE

WEST MEDFORD POST OFFICE,ON THE OUTSIDE OF A LONG CURVE IN THE

TRACK, 70 YARDS SOUTH OF A STONE BUILDING BETWEEN THE TRACK

AND MYSTIC VALLEY PARKWAY, 3 FEET SOUTH OF A TELEPHONE POLE,

15 1/2 RAILS SOUTH OF MILEPOST B 7, 98 FEET EAST OF THE EAST

CURB OF THE PARKWAY, ABOUT 1 FOOT BELOW THE LEVEL OF THE TRACK

AND SET IN THE TOP OF A CONCRETE POST THAT IS 4 INCHES

UNDERGROUND.

 

First off, forget the GPSr except to get you to the area. With a scaled location that's as far as its usefulness will go.

 

I would start with the longest distance and work in:

 

1. - ABOUT 0.5 MILE SOUTH OF THE WEDGEMERE STATION, 1.3 MILES NORTHWEST OF THE WEST MEDFORD POST OFFICE

 

OK, presumably you know those landmarks so that puts you near the target. Presumably you can park off of the parkway and walk over to the tracks. And be sure you stay on the outside of the curve, which is towards the parkway. Don't cross the tracks. BTW: is this an active line? CAUTION - you might get arrested or killed!! Moving right along:

 

2. - 15 1/2 RAILS SOUTH OF MILEPOST B 7.

 

You are right, a rail is a length of track. HOWEVER many of these lines have replaced the old rails with welded rail so you can't count track segments. Most rails were 39 feet long so do the arithmetic

 

distance = 15.5 x 39 = 465 feet = 155 yards.

 

Pace it off. For me a pace is just short of a yard so if I take big steps I can get pretty close.

 

3. - 98 FEET EAST OF THE EAST CURB OF THE PARKWAY

 

This is probably just outside of the tracks, assuming the parkway and rails are nearly parallel.

 

4. - 70 YARDS SOUTH OF A STONE BUILDING BETWEEN THE TRACK AND MYSTIC VALLEY PARKWAY

 

I would use Google Maps or Google Earth to spot that building. I would guess the area between the parkway and tracks is not private houses, so this might be an old railroad building. You think you know which one it is, so start with that and see if it agrees with the other distances.

 

5. - 3 FEET SOUTH OF A TELEPHONE POLE

 

This is your best bet. The age of poles can be deceptive, so go with what's there as long as it's consistent with the other numbers. If the pole you found matches the other numbers, it's probably right.

 

6. - SET IN THE TOP OF A CONCRETE POST THAT IS 4 INCHES UNDERGROUND

 

Hah! Gotcha! It sound like you have to dig or use a metal detector. Surfaces can change, but if anything railroad rights-of-way tend to get higher (always dumping ballast on them) so this might be deeper. OTOH, being underground may have protected this from damage. Spend some time and you might get it. Just watch out for trains and RR police.

 

One last observations: distances tend to be given in units inversely proportional to their accuracy. So the .5 miles and 1.3 miles may be off by .1 mile, the yards will probably be from the guys pacing it off and the feet were probably measured with a tape.

Edited January 15, 2008 by Papa-Bear-NYC

[+pgrig]

Dear BlkDogTrkrs--

 

No, it gets worse . The roadbed is covered with 2-3" sharp-edged gravel, perhaps 6+ inches deep and extending (in all liklihood) over "my" BM, which yes, I saw was subtrerranian. And (another sigh) I have learned enough to know that "scaled is bad, adjusted is good" (like, as the famous pig said, "two legs bad, four legs good").

[NGS Surveyor]

Don't feel bad if you're having a little trouble. Remember, until small, handheld GPSr came along about 10 years ago, this is the way we looked for ALL survey marks. In fact, I would suggest that anyone wanting a challenge - turn off your GPSr for a few recoveries. Then study the description, recovery notes, and maps in detail and then go hunting.

 

GeorgeL

NGS

[+Black Dog Trackers]

Heh, well this one will be difficult. A metal detector might help, but it also might be driven crazy by all the metal that's usually around railroad tracks.

 

By the way, I looked in Google Earth and the mark is shown on the wrong side of the tracks. But anyway, for amusement here is a nice view of the area. (I don't know how to put coordinates in this viewer, though.) Be sure to use the rotate buttons! Also the zoom in if it isn't zoomed in already. I see the poles and wires going along the tracks there.

Edited January 15, 2008 by Black Dog Trackers

[2oldfarts (the rockhounders)]

Since you know the location of the foundation of the building that is referenced in the description, that would be the starting point. Head south for 70 yards and look for a telephone pole. Odds are in your favor that the pole is in the correct position even if it is a different pole. It is common to replace a pole at the same spot the old one is removed from.

 

The second key is to measure from the parkway to the telephone pole (98 feet) and compare the description with what is actually there at this distance.

 

If the pole is still standing, time to use the metal detector. Lacking that, a long handled screwdriver can be used as a probe. Measure (pace) 3 feet south and see what is there.

 

Good luck,

 

John

[+Black Dog Trackers]

Another problem I see is that the viewer shows 2 sets of track but the description only speaks of one track. Which track is which?

[Bill93]

Sounds like you've picked a hard one. Try some others in the area. A few successes will greatly improve your feel for the situations where marks are placed and the techniques for finding them. Come back to this one when you get bored with easy ones.

[mloser]

I agree that you have picked a tough one, but it isn't impossible. Obviously everyone here has their approach to finding a mark like this, and there are some great hunters giving advice.

 

Here is how I would approach it:

 

First, looking at Topozone shows me that it isn't too far from the indicated coords, but that it is indeed on the west side of the tracks as suspected. The triangle symbol also tells me that it was at one time a mark used for horizontal control, although it doesn't seem to have been logged anywhere that way, including the Mass Highway Department, which has a mark labeled "5 S" (query for it here) but no description save that it is 2 inches underground, and also promises a sketch but the link is bad. But the presence of a horizontal symbol leads me to believe that the location of the mark on the map is pretty accurate, and that means it isn't too close to the tracks.

 

Next bit of research is to find similar marks. I looked at GC.com and found 5 M, which Shorelander previously found and photographed. This is both good news and bad. The good news is that the mark is pretty far from the tracks, and that gives reason to think that your mark may also be a similar distance. Also, the description for 5 M puts it near a pole and confirms what I have found in my area--that these marks are usually set in line with the telephone/telegraph poles. The bad news is that the poles are gone at 5 M, so yours may also be, but BDT said he saw the poles in the aerial view (and in fact, returning to his link I see them also. I have marked the photo to show the pole but the image is a bit small to see it easily:

Look at BDT's link for a better view). So maybe there isn't any bad news!

 

Armed with that info, I would simply go the pole in question. It is the one across the tracks and just to the north of the coordinates from the GPSr. I would then measure 3 feet south of the pole (in line with the next pole) and metal detect for the disk (without a metal detector you need to probe or simply dig. I have found that when probing you will hit something hard that has a solid ring to it. By probing from the sides you can confirm that what you are poking at extends deep into the ground, and then dig). If that failed I would measure the 98 feet from the road to see if I was in the right place and again metal detect. If all else failed I would pace off the distance to the old foundation and the milepost to see if I had the right pole. If that still didn't work I would use my 100 ft tape to actually MEASURE those distances as best I could and again search. However, doing that is not a simple task alone with a 100 foot tape, and would also be pretty inaccurate, so I would be more likely to dig a lot of holes before I did it.

 

By the way, this mark is pretty poorly described, and also poorly placed. The reference points are all pretty distant and hard to measure from. A better placement would have put the mark much closer to the milepost or to some other object that was 25 or less feet from the mark. 5 M at least was a measurable distance from a trackside box, even though it is now gone!

 

Good luck with it!

Edited January 15, 2008 by mloser

[+Holtie22]

One more piece of advice. As mloser has noted, the triangle symbol on the topo map indicates a horizontal control station. (although on the 1946 topo that I linked to in another thread, this BM appears with an "X" rather than a triangle). Since the maps were made by USGS, it stands to reason that they would have the horizontal control data if any were available. You can try contacting USGS as discussed in the previous thread, keeping in mind that their data is probably in the NAD27 datum and probably third order accuracy. All of which will still leave you probing or digging over a larger area than you would hope!

[+GEO*Trailblazer 1]

Don't feel bad if you're having a little trouble. Remember, until small, handheld GPSr came along about 10 years ago, this is the way we looked for ALL survey marks. In fact, I would suggest that anyone wanting a challenge - turn off your GPSr for a few recoveries. Then study the description, recovery notes, and maps in detail and then go hunting.

 

GeorgeL

NGS

 

Yes that is a good idea.

Makes you use your brain more and will also get you just as close sometimes.

 

I like hunting them at night.

But I have not been out doing that for a while.

Talk about a challenge.

[+jwahl]

The oblique view from the west clearly shows wires and poles. If the white square thing shown on the overhead in google earth is the building, then the 70 yards puts it about lined up with the southerly baseline of the tennis courts. Since it was demolished it shows up in some photos and not others.

 

In this view there is a pole at about that location.

 

Oblique view of Area

 

It looks like you might have to rotate that view so you are looking west by doing one click on the counterclockwise icon.

 

If the building is not there adjust accordingly, to one pole up or back. The location also fits the coordinate latitude fairly well. If additional tracks were laid, even the poles could have moved. The 98 feet from the road would verify if they are about in the same place or not and seems to fit well from the photos.

 

- jlw

Edited January 16, 2008 by jwahl

[mloser]

That white square thing is most likely a signal control building--you can see the disturbed ballast from it to what is most likely a signal post just to the north northeast. Chances are it was recently put in since it is on some of the pics and not others.

 

Just to the northeast of that white building is a driveway from the road to nowhere. I suspect that was a driveway to the now demolished stone building. Pgrig pointed out the he found the remnants of the foundation of that building. I'd like to think I saw part of one of the walls of it in the aerial photo but I wouldn't bet much on it.

 

Based on the similar nearby mark (5 M) set at the same time I think there were 2 tracks there when the marks were set. 5 M appears to be the specified distance from the tracks, and it is on the same side of the tracks as this mark, so the evidence is that there were always two tracks here, and that the number of tracks just wasn't mentioned.

[+pgrig]

You guys are amazing! If I sit here long enough, I'll probably see you dig the BM up remotely and photograph it for me!

 

[i am looking at Google Earth and MS Virtual Earth for the first time in this thread, so my head is still spinning a bit. ]

 

Mloser, I believe you have nailed the details correctly [Wow!]. The bright white square thing just on the west side of the tracks is a newish signal control shack, with a signal standard about 10 ft. NE of it and another on the E side of the tracks. You are also right (!) that the "driveway to nowhere" off the parkway is in fact the access to the (now demolished) "stone building", whose E wall foundation is about 90 ft. NW of the signal shack.

 

If I remember my tromping around correctly, my best guess as to the correct telephone pole was one about 20 ft. S of the signal shack, but now, after all this help, and understanding what a "rail" is , I will need to go back (after the snow melts a bit), check my measurements, and hunt some more.

 

I'll bet I find it!

 

Thanks again.

[mloser]

I'm betting it is the second one south of the signal shack! I originally thought it was the 3rd south of the shack, and the first one south of the tennis courts, but based on some measuring I did on the Virtual Earth site I changed my mind.