Question About Bh

[+fly46]

I was just wondering how benchmark hunting differs from hunting for a regular cache and any changes to routine you might have to make?

 

I'm going to do a cache day in Conneaut (two towns over) and I know there's at least one benchmark, so I was thinking of getting that one, too.

[+GEO*Trailblazer 1]

The only difference is the type of thing you will find.

A disc,church spire,mast,water tower,etc.

 

Just plug in the coordinates and go looking for it.

 

Have fun and lots o luck.

[ckhd]

I usually don't use the coordinates. I go by description, and have coordinates as a backup. The listed coordinates can be as much as 500' off. Quite a bit of area when you are searching for a small benchmark disk.

[+Black Dog Trackers]

fly46 -

 

Actually hunting for geocaches and hunting for benchmarks are really very different activities. Before you go, you should read the benchmarking FAQ page. That page explains what ckhd is talking about in the section called "Why do the coordinates of some benchmarks seem to be way off?".

Edited March 29, 2004 by Black Dog Trackers

[+road_rascal]

So, when I see 'location had been adjusted' I can assume that the coordinates I punch into my GPSr can be fairly accurate, whereas 'location is scaled' means I should leave the GPSr in the truck go hunt for the BM using other visual references. Correct? 16 hours at work is wrecking my thought process .

[+fly46]

Very cool, guys! Thank you!

[+California Bear]

So, when I see 'location had been adjusted'  I can assume that the coordinates I punch into my GPSr can be fairly accurate, whereas 'location is scaled' means I should leave the GPSr in the truck go hunt for the BM using other visual references.  Correct?  16 hours at work is wrecking my thought process  .

Yup!

 

About the only time I use the GPSr anymore is when the area has dramatically changed (i.e. description talks of sand dunes and I pull up to find a housing tract) to get an approximate location for a 'used to be here but probably not anymore' photo.

 

I have also found that USGS maps can be helpful. Some benchmarks are noted on the maps and may be more helpful than the GPS. In addition, because some of the maps have been revised in many moons, features mentioned in a recovery may still be on the map while they have been demolished/altered in the real world.

Edited March 30, 2004 by California Bear

[+seventhings]

I think most experienced and successful benchmark hunters eventually come to the realization that the DATASHEET rules and the GPSr is just another tool in the kit. And reading the datasheet three times and building a mental image of where the mark is in relation to the described environment is more useful than plugging the coords into the GPSr's GOTO.

 

I use my GPS' GOTO function to tell me when to start looking for a place to park as I approach a benchmark. Once I leave the truck and start looking, however, I rely more on a rigid metal prod and a tape measure than the GPS.

 

7

[+GEO*Trailblazer 1]

Most people I know do that with a cache too.

 

I was merely relating to his question in general not a detailed analysis.

 

The GPS serves the same function in both aspects it gets you to point )A.

From there you have to use your noggin© anyway whether it's a cache,benchmark,body,building,gold bar(Yea)etc.

[GeoTeam66]

Benchmarks are actual marks used by engineers, and are not hidden by geocachers. Geocachers hide containers, but benchmarks are like little disks thant were not meant to be hidden (or at least the engineers didn't think people would hunt for them when they were placed).

[+GEO*Trailblazer 1]

I think the Engineer's did want to go back and find them if needed,or they would not have spent so much time and money making sure they were of a permanent type of setting.

 

After all they are the CONTROLS for the maps.

[+Colorado Papa]

I was just wondering how benchmark hunting differs from hunting for a regular cache and any changes to routine you might have to make?

Forget about starting with the GPSr. Start with the datasheet and go by the description. If things have changed so that even the description is not up-to-date, go to the library and do some research about how things used to be back when the BM was installed. If you're lucky, things will fall into place and you may find the BM, then use the GPSr to check and log the coordinates.

[+Black Dog Trackers]

Well, I really like my GPSr. I like watching the mark's position get closer on it as I drive. 2.38 miles .... 1.22 miles ... 438 feet; big excitement! I like seeing all the side roads, railroads, and creeks go by on it too.

 

To reach a mark, I first look at my map of the day's PIDs and select one. Next, I punch the GoTo button and select that PID. Next, I read the datasheet to figure out which side of the road the mark is on. Next, I start driving toward the mark. I use the GPSr to find the place to park my car.

 

In the case of a scaled mark, before I get out of the car, I examine the surroundings compared to the to-reach instructions on the datasheet to see if I need to move my car. Then, I walk to the mark's position as described in the to-reach instructions on the datasheet.

 

In the case of an adjusted mark, I use the GPSr further to walk to get within 20 feet of the mark. Then if I don't immediately see the mark, I examine the surroundings compared to the to-reach instructions on the datasheet.

 

I like to find adjusted marks with only the GPSr if I can. It may not be the most efficient way, but it is the way that's the most fun for me. It's sort of like a pleasant little surprise to find it that way, I guess.

 

After I find the mark, then I compare its location with the to-reach instructions to see if they need updating. In the case of a scaled mark, I also write down the averged position from the GPSr for it.

[+GEO*Trailblazer 1]

Well, I really like my GPSr. I like watching the mark's position get closer on it as I drive. 2.38 miles .... 1.22 miles ... 438 feet; big excitement! I like seeing all the side roads, railroads, and creeks go by on it too.

 

To reach a mark, I first look at my map of the day's PIDs and select one. Next, I punch the GoTo button and select that PID. Next, I read the datasheet to figure out which side of the road the mark is on. Next, I start driving toward the mark. I use the GPSr to find the place to park my car.

 

In the case of a scaled mark, before I get out of the car, I examine the surroundings compared to the to-reach instructions on the datasheet to see if I need to move my car. Then, I walk to the mark's position as described in the to-reach instructions on the datasheet.

 

In the case of an adjusted mark, I use the GPSr further to walk to get within 20 feet of the mark. Then if I don't immediately see the mark, I examine the surroundings compared to the to-reach instructions on the datasheet.

 

I like to find adjusted marks with only the GPSr if I can. It may not be the most efficient way, but it is the way that's the most fun for me. It's sort of like a pleasant little surprise to find it that way, I guess.

 

After I find the mark, then I compare its location with the to-reach instructions to see if they need updating. In the case of a scaled mark, I also write down the averged position from the GPSr for it.

The only thing I do different is I use the reading aquired for that mark as,

My new Control

From experience the Million $$$$+++++Readings from the Sats are extremely more accurate than anything present today.

We could go into a lengthy discussion on accuracy,But as for me the readings are precise. (CONTROL)

Otherwise they would not be letting us turn the readings into them to help update maps.(just my opinion).

 

I really like watching my GPSr and the GO TO function as well,Just like a Pilot Navigating in on a Point.

 

Remember your GPSr is a sighting device,and is only as good as the person who sights it in.

If you use certian (CONTROLS) you can be deadly accurate.

 

To answer the question more precisely,

Everyone uses all the clues,data sheets,cache pages,Historic references etc.. they can get to find a point,no matter the point you are looking for (something at that point).

 

After finding over 500 logable(NGS) and 500+,PLSS,Army Corps of Engineer's,Department of the Interior,United States Engineer's,RLS disc's and corners.Patented Land Corner Stones dating to late 1800's and Early 1900's.

 

Oh yea there's the one Map Carved in Stone that dates to 600 A.D.Anasazi ,and the Old Spaniards Trail Map Carved in Stone,with the Conquistadors names that dates to the 1600's.

There are not maps and clues to these,but I still found them.

 

So just by being observant and looking things over, one never leaves no clues of their passing.

I am also a Tracker as well and learned to see signs of passing and the like and to look for the things that are out of place.

 

These are but a few of the talents I use when searching.

[+road_rascal]

Another dumb question: so when you research a BM on Geocaching.com/mark, find the one you want, and the location has been been adjusted (meaning it's GPSr friendly), is it safe to say you can use the coordinates that are posted on the Geocaching site or should you use the ones that are on the original PID datasheet? The only reason I'm asking this is because I went to look for one that was supposedly 7 feet from a telephone pole and the adjusted coordinates put me over 300 feet away.

[ckhd]

It was probably coordinates for NAD27, which is different thatn NAD83 (WGS83). I made the same mistake and ended up 1/2 mile from where I was headed.

 

The ones you find on the geocaching website are in WGS83 format. If they are adjusted, use them. If you use the originals, you will probably be way off (like your telephone pole incident).

 

Scaled coordinates can be off, and usually are. Adjusted coordinates will be more accurate than your GPS

Edited April 8, 2004 by ckhd

[+GEO*Trailblazer 1]

I disagree.

Your GPS will be more accurate than any scaled or adjusted mark!

Or they would not be having us turning in readings to the update at the National Map.

 

I should explain a little more.

You get a GPS freindly + - 600 feet.From Geocaching and the NGS.

The accuracy of the GPS is 5-10 feet.

 

Now start with your closet Triangulation Station to you.

Use the reading after you have let your GPS set for a while,do not just take a fast reading.

Use these readings as your new(Control) for that Point.(Survey Control),Then consecutively get all the triangulation tied in .and use these readings for your new (Control.)

I believe that is the meaning of superseded control.

 

That is why hiding and finding caches is much easier they are already GPS freindly.

 

We would have to have a 6 month seminar to go into all the aspects of the why the readings are adjusted from the Magnetic Meridian rule to the True Meridian rule.

The Annual westward slippage, proper motion of the stars and the New Geoid model and well.....I studied it a long time and am still trying like all the other Scientists to unravel the Mystery's of the Magnetic Field and the Westward movement of the North Star.

 

And the more you learn, you will find the less you know.

 

And more the equiptment to do your research costs.

[ckhd]

And more the equiptment to do your research costs.

Man, I find that is the case in anything!

 

Yeah, I'm no expert, but my understanding is that adjusted coordinates are sub-inches accurate.

 

I knew that scaled could be pretty far off.

 

I'm not sure where I got the idea of adjusted coordinates being accurate. Am I wrong?

[+happycycler]

NO! ckhd, you are not wrong -- the adjusted latitude / longitude coordinates are very accurate. On a good day our toy GPS will read close to published adjusted coordinates but are NOT more accurate. I have seen cases where my Magellan Merigold would read 3 or 4 feet while setting on a triangulation station. I believe that is just a lucky day, with freak atmospheric conditions. I am sure that the professionals here can explain it better.

[+GeckoGeek]

I disagree.

Your GPS will be more accurate than any scaled or adjusted mark!

Or they would not be having us turning in readings to the update at the National Map.

Bullspit.

 

The common consumer GPS doesn't display enough numbers to get much more accurate then 6 feet. The NGS datasheet for an adjusted mark has two more digits then the GPS giving 100 times the "granularity". (Be sure you're looking at the original NGS datasheet, not GC's version.)

 

I don't know why anyone wants the GPS readings for an adjusted benchmark. Perhaps it's a "reality check" to make sure the readings you're tuning in in isn't whacked out. The NGS sure isn't asking for them. They've got the mark down to inches or less.

 

Scaled coordinates is a completely different story. It's someone's guess based on looking at a map.

 

Survey-grade GPS units ($3000+) could be a different story. They use a second frequency to help figure things out.

Edited April 9, 2004 by GeckoGeek

[+road_rascal]

It was probably coordinates for NAD27, which is different thatn NAD83 (WGS83). I made the same mistake and ended up 1/2 mile from where I was headed.

 

The ones you find on the geocaching website are in WGS83 format. If they are adjusted, use them. If you use the originals, you will probably be way off (like your telephone pole incident).

 

Scaled coordinates can be off, and usually are. Adjusted coordinates will be more accurate than your GPS

No, I used GC.com's coordinates and they were off. I didn't find the mark, and that may be due to new construction in the area. I'm going back out to the site next week (this time with help) and see if I can find it. The phone poles are still there but the ground was pretty muddy and I didn't look very hard the first time. I just went by the GPSr coords I punched in.

[2oldfarts (the rockhounders)]

It was probably coordinates for NAD27, which is different thatn NAD83 (WGS83).  I made the same mistake and ended up 1/2 mile from where I was headed.

 

The ones you find on the geocaching website are in WGS83 format.  If they are adjusted, use them.  If you use the originals, you will probably be way off (like your telephone pole incident).

 

Scaled coordinates can be off, and usually are.  Adjusted coordinates will be more accurate than your GPS

No, I used GC.com's coordinates and they were off. I didn't find the mark, and that may be due to new construction in the area. I'm going back out to the site next week (this time with help) and see if I can find it. The phone poles are still there but the ground was pretty muddy and I didn't look very hard the first time. I just went by the GPSr coords I punched in.

 

It appears as though you may have transposed two numbers when entering the coordinates. It a simple mistake MOST of us make at least once.

 

Good luck.

 

John

[+road_rascal]

It appears as though you may have transposed two numbers when entering the coordinates. It a simple mistake MOST of us make at least once.

 

Good luck.

 

John

Nope. I triple checked coords to make sure I didn't goof something up. I'm going to get a few this weekend that are out in the open without any overhead interference (high tension wires, etc) and see if the coords on my GPSr agree with the coords on the GC.com site.

[+GEO*Trailblazer 1]

Well I have some that you ought to come and try to find with NGS or Geocaching coords,

 

I bet with what I have I can get you closer than the mark than that.It is probably just something that I am doing ??? that works and I am going to keep working on.It works very accurately for me.

 

And I have learned not every one accepts a theory until it is a proven fact then it becomes a natural law.

 

Yea I do have some BULLSPIT,full of bullspit and I have some COW spit too!!,

a little dog and cat,mice in the barnspit,and even a little guanospit.It is some real good fertilizer.

[+GeckoGeek]

I bet with what I have I can get you closer than the mark than that.It is probably just something that I am doing ??? that works and I am going to keep working on.It works very accurately for me.

Can you point out some of the marks you are talking about? If these are ones where the position is adjusted, and you've found them and the error is well outside of the normal GPS error, I'd be very surprised. Having the height adjusted doesn't count.

 

If the position is scaled, then what you say is exactly right -use the GPS to get you in the area, but use the description to get you to the spot.

 

One of the rules of the universe is "spit happens". It's possible that there was a data entry error between the datasheets and entering them into the computer. If there has been no recovery since the sheets have been computerized, then you may be the first to discover it.

 

But the other statement hasn't been addressed. Can anyone show any official that's interested in the handheld GPS coordinates of triangulation stations? True benchmarks (scaled), yes, but not adjusted ones.

[+GeckoGeek]

Another dumb question: so when you research a BM on Geocaching.com/mark, find the one you want, and the location has been been adjusted (meaning it's GPSr friendly), is it safe to say you can use the coordinates that are posted on the Geocaching site or should you use the ones that are on the original PID datasheet?

Can you give a PID of the one you're looking at? In general, the coordinates listed on the top of the page in CG.com should match the ones on the original datasheet on the line that starts with "* NAD 83". I don't think anyone has reported a parsing error between the original sheets and what CG posts, but it could happen.

 

Also keep in mind that telephone posts do move over a long enough period of time. The road could have been realigned or all the poles could have been replaced. Perhaps the utilities went underground and there are no telephone poles - just light poles.

 

Last, have you checked what your GPS's EPE display was at? When first turned on mine can be a few hundred feet until it has a chance to fully lock in over a course of several minutes. People have reported stranger things happening to their units. Best theory is that somehow the almanac got corrupted.

[K9 Crew]

The phone poles are still there

But are the poles in the same place they were when the data sheet shows the description from the pole? In my area if they change one pole, it is usually in the same hole. But due to the changing ownership and buildings being built, I have seen the upgrading of the whole line, be moved many feet from the original.

 

Willy

[CallawayMT]

I disagree.

Your GPS will be more accurate than any scaled or adjusted mark!

Or they would not be having us turning in readings to the update at the National Map.

 

I should explain a little more.

You get a GPS freindly + - 600 feet.From Geocaching and the NGS.

The accuracy of the  GPS is 5-10 feet.

 

Now start with your closet Triangulation Station to you.

Use the reading after you have let your GPS set for a while,do not just take a fast reading.

Use these readings as your new(Control) for that Point.(Survey Control),Then consecutively get all the triangulation tied in .and use these readings for your new (Control.)

I believe that is the meaning of superseded control.

 

That is why hiding and finding caches is much easier they are already GPS freindly.

 

We would have to have a 6 month seminar to go into all the aspects of the why the readings are adjusted from the Magnetic Meridian rule to the True Meridian rule.

The Annual westward slippage, proper motion of the stars and the New Geoid model and well.....I studied it a long time and am still trying like all the other Scientists to unravel the Mystery's of the Magnetic Field and the Westward movement of the North Star.

 

And the more you learn, you will find the less you know.

 

And more the equiptment to do your research costs.

I respectfully disagree, there is no possible way that you are getting more accurate coordinates with your handheld than any adjusted coordinates. You may get close at times(within a foot or two), but you will never even duplicate yourself when you go back to the same point. You are talking about adjusted coordinates which are accurate down to the centimeter accuracy, your handheld can't even read to that level.

 

As to the updating of USGS quads, I think that is great that you are doing that work and it will be good to see the quads updated, but the USGS is accepting your work because it does fall into the National mapping standards as shown here from the USGS mapping website:

 

United States National Map Accuracy Standards

With a view to the utmost economy and expedition in producing maps which fulfill not only the broad needs for standard or principal maps, but also the reasonable particular needs of individual agencies, standards of accuracy for published maps are defined as follows:

 

Horizontal accuracy. For maps on publication scales larger than 1:20,000, not more than 10 percent of the points tested shall be in error by more than 1/30 inch, measured on the publication scale

 

For a 1:24000 scale quad this equates out to meaning that 90% of your points must fall under approximately 67' and 10% may fall over 67' in error. These do fall well within the accuracy of your handheld GPS.

 

Superseded control on the NGS data sheets refers to the control that has been superseded by updated control such as NAVD88 superseding NGVD29 and NAD83 superseding NAD27.

 

I'm not sure where you are going with the magnetic, true or slippage theory's, but I do know that you are not using the new geoid model in your GPS and it has no effect on the horizontal accuracy of any marks. The geoid is only used to determine elevations based upon GPS heights.

 

I am no expert, but I do know that you cannot get better coordinates on NGS adjusted horizontal control using a handheld GPS.

 

Regards,

CallawayMT

[+road_rascal]

OK- here's one that I absolutely know that the coords are wrong, even though it says the coords are adjusted. This benchmark's coords are listed as being on the north side of the highway when in fact it is located at least 200 feet away on the south side. Always has been, and I confirmed that fact with the Fire Chief from the next town over (he's my father-in-law). The detail sheet does not give accurate directions to the site and all of the online maps point to a location north of the highway (and my GPSr pointed that way too once I got close to the location).

[+embra]

Interesting...usually the altitude is adjusted and the location is scaled. It looks to me like those specifications got flipped on the data sheet...and your observation would support that notion. Worth reporting, I would think.

 

BTW, I like the designation of nearby station BORG.

[+road_rascal]

I'll give one more. This benchmark's coords send me to a trailer park and I did not see a concrete base for a water tank. I wouldn't think that the city would tear down a water tank that was constructed in 1959, but I could be wrong, considering that there are two in the area.

[+Colorado Papa]

I wouldn't think that the city would tear down a water tank that was constructed in 1959, but I could be wrong, considering that there are two in the area.

Where did you get the info the tank was constructed in 1959?

 

From what I can determine, the age of the tank was not mentioned when it was observed as a benchmark in 1959. It could have been constructed forty or more years earlier.

 

I've come across several locations where tanks were torn down and something else was located there. Is there a tank nearby that can be observed with a ball on top?

Edited April 12, 2004 by Colorado Papa

[+rogbarn]

Interesting...usually the altitude is adjusted and the location is scaled. It looks to me like those specifications got flipped on the data sheet...and your observation would support that notion. Worth reporting, I would think.

Intersection points (tanks, towers, radio masts, etc) always have adjusted coordinates because of the nature of how they are observed. Their coordinates are computed by triangluation from multiple points that already have high level adjusted coordinates. On the other hand, intersection points usually do not have any height computed at all, or if a height is listed, it is often scaled. These points are horizontal controls points only, not vertical. This is a typical situation.

[+Colorado Papa]

OK- here's one that I absolutely know that the coords are wrong, even though it says the coords are adjusted.  This benchmark's coords are listed as being on the north side of the highway when in fact it is located at least 200 feet away on the south side.  Always has been, and I confirmed that fact with the Fire Chief from the next town over (he's my father-in-law). 

Was your father-in-law born before 1930? The tower for the benchmark was observed in 1934 and may have been replaced by the steel structure you photographed. Look around the base an see if you can find a date or indication the tower is over seventy years old. On the other side of the road, see if there is any indication that something may have been there prior to WWII.

[+GeckoGeek]

road_rascal, I've looked at the sheets. Yes, they are adjusted, but they are landmarks which raises the distant possibility that you are not finding the original structure.

 

If you want to run a "sanity check" look around at nearby stations and see if the "scorebox" shows the tower/water tank you're talking about. Run the math and see if those measurements support the idea that the datasheets are wrong.

 

Both of these had to be transcribed from paper to computer and there are no official observations since then. I would not rule out data entry error. If that was the case, then the the scorebox should shed some light on this. I understand the scorebox is measured values, not calculated ones.

 

The first step in determining if the structures you've observed are indeed the original marks is to find out when those structures were erected and see if it's consistent with the monumented date.

[+road_rascal]

I'll call the ranger station and see if I can't get ahold of someone who knows the history of the lookout tower dating back to the 1930's. Otherwise I'll re-enter the log as a 'not-found' and post an explanation. I wonder why the NGS would go through the trouble of updating the logs with current GPS coords if the station has not been recently recovered?

[+Colorado Papa]

I wonder why the NGS would go through the trouble of updating the logs with current GPS coords if the station has not been recently recovered?

I should let Dave answer this one, but I feel that this is exactly what they are trying to do, get old records updated!!!

[TerraVador]

This tower has been moved. I am quoting from GRANTSBURG :

QO0295

QO0295 STATION RECOVERY (1960)

QO0295

QO0295'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1960 (FAR)

QO0295'STATION RECOVERED AND FOUND IN GOOD CONDITION. THE GRANTSBURG

QO0295'LOOKOUT TOWER HAS BEEN MOVED AND IS NOW LOCATED ABOUT 0.1

QO0295'MILE SOUTH-SOUTHEAST OF THE STATION. A REQUEST WAS RECEIVED

QO0295'TO MOVE THE U.S. GEOLOGICAL SURVEY MARK THAT WAS UNDER THE

QO0295'CENTER OF THE TOWER AS A STREET IS PLANNED FOR THE LOCATION.

QO0295'FUTURE CONSTRUCTION PLANS WERE DISCUSSED WITH MR. PAUL A.

QO0295'OLSON, VILLIAGE PRESIDENT, AND NO OTHER MARKS AT THIS STATION

QO0295'APPEARED TO BE IN DANGER OF BEING DISTURBED.

 

Therefore, GRANTSBURG LOOKOUT PID=QO1549 should now be marked as DESTROYED.ROAD RASCAL should email Deb Brown and point this out along with his personal observations.

 

Reading further, probably so should GRANTSBURG PID=QO0295 (unless they never actually found the disk):

QO0295

QO0295 STATION RECOVERY (1966)

QO0295

QO0295'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1966 (EBB)

QO0295'THE STATION MARK WAS DESTROYED DURING THE CONSTRUCTION OF A

QO0295'NEW HOUSE, WHICH IS BUILT DIRECTLY OVER THE STATION SITE. REFERENCE

QO0295'MARK NO. 2 HAS BEEN DESTROYED BY THE CONSTRUCTION OF A SIDE

QO0295'STREET. REFERENCE MARK NO. 1 AND THE AZIMUTH MARK WERE

QO0295'DESTROYED AT THIS TIME. GRANTSBURG TOWER RESET (USGS) WAS

QO0295'RECOVERED AND FOUND IN GOOD CONDITION. THIS MARK WAS LEFT

QO0295'IN BECAUSE IT IS IN NO DANGER OF BEING DISTURBED

 

If you get good GPS readings of a location adjusted mark that are far off from the published coords, it bears further investigation!

[+Colorado Papa]

I am quoting from GRANTSBURG :

 

QO0295

QO0295                          STATION RECOVERY (1960)

QO0295

QO0295'RECOVERY NOTE BY COAST AND GEODETIC SURVEY 1960 (FAR)

QO0295'STATION RECOVERED AND FOUND IN GOOD CONDITION.  THE GRANTSBURG

QO0295'LOOKOUT TOWER HAS BEEN MOVED AND IS NOW LOCATED ABOUT 0.1

QO0295'MILE SOUTH-SOUTHEAST OF THE STATION. 

 

Mystery solved!The picture looked like a much newer tower than one built more than 70 years ago. As a kid growing up in Minnesota, I can remember wooden towers. (BTW, I was born in 1929.)

Edited April 13, 2004 by Colorado Papa

[+Reco Van Reco]

Today I looked for PM0043. Discribed as a "rivet". I was suppose to be near a site of a Rail Road bridge (5' west 1' below west rail). I found the area described on the site. However I don't know what a rivet is. Would it be "riveted" to the cement embankment as described, or are they "driven" like a stake into the ground? The date last checked on the Geo web site say's 1934, the bridge was removed in 1955. However the bridge embankment where the rivet supose to be is still there. Am i wasteing my time looking for this? This bench marking is starting to be an adiction for me. Any help would make me smile. Thanks. A benchmark rookie.

[+Kewaneh & Shark]

Reco van Reco -

 

Most rivets that are placed around railroad tracks are of the type used in the rail connecting joints. They were oftentimes placed in the wet concrete of the bridge abutments. The exposed rivet heads were used as benchmarks. If the bridge abutment is still there, there's a good chance that the rivet is still there too. If it is one of the rivets used as a rail connector, you'll most likely see a metal disk about 1.5" diameter with a highly convex top (more convex than a traditional benchmark). Most rivets have no markings. Pay particular attention to the description and any tie distances in the description.

 

Good luck in your hunts.

- Kewaneh

[+embra]

There are pictures of a couple of rivets on dustyjacket's page.

[+road_rascal]

THANK YOU TerraVador! I was going to look into it further today but work (at and away from home) has kept me so dang busy I never had a chance. Thanks again !