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Details for Benchmark: MH0134

N 41° 01.750 W 092° 48.683 (NAD 83)

Altitude: 961.59

Coordinates may not be exact. Altitude is ADJUSTED and location is SCALED. (more info)

Location:
In MONROE county, IA View Original Datasheet
Designation:
Y 111
Marker Type:
bench mark disk
Setting:
set into the top of a round concrete monument
Stability:
May hold, but of type commonly subject to surface motion.

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Signal building has been removed and replaced with a new one on the other side of the tracks. Post found broken and tilted so no longer marks intended elevation.

[Photos:]
photoMH0134-Y_111-2-20180826.jpg
Showing post tilted
photoMH0134-Y_111-3-20180826.jpg
Area

Good and per previous description. Disk projecting 6 inches.

Building is 8.8 ft high so a GPS antenna pole should be quite tall.

[Photos:]
photoMH0134-Y_111-1-20170624.jpg
.
photoMH0134-Y_111-3WSW-20170624.jpg
.

Heading to MOGA grabbed a few caches and a few benchmarks

[Photos:]
photoMH0134

Found this benchmark

biscuitt

[Photos:]
photoIMG_4561[1]

Found in good condition, about 26 feet west of center of north D street, which appears widened in recent decades, 36 feet south of main track (which is south of a major spur line), 25 feet south of a side track, 1.5 ft south of the southeast corner of concrete signal building 304.1, and 0.8 ft above base of rail. Stamping 'Y 111 1935' Handheld coordinates N41 01 45.8 W092 48 47.7, sky obscured by building.


Originally, I didn't trust this one with discrepancies on the street distance and relative height above the track, and no mention of the signal building. A point 36 ft west of the street would better fit the elevation relative to the track. Did someone re-plant the post in a convenient place after grading and installing the building?

The street here is a few feet wider than that further south but is still pretty much on the same center line, although it isn't exactly straight. Probing finds the post is at least 3 ft long, so it isn't just a broken stub that got replanted. The nearest pole is newer and 40 ft away, so is irrelevant. It is not obvious whether the track has been raised since 1935, although that is common.

I'm told these signal buildings were shipped in on rail cars and dropped in place, probably in the 1940's or 50's, so it is believable the post could have been undisturbed.

[This entry was edited by Bill93 on Friday, December 30, 2005.

[This entry was edited by Bill93 on Sunday, May 03, 2009 at 6:08:18 PM.]

A leveling run from MH0135 Z 111 at post office with expected accuracy +/- 0.050 ft found MH0134 to be 0.005 ft too low-essentially perfect. Therefore I will report this mark as Good.

Methods: Topcon AT-F4 (good construction grade) automatic level and a rod with 0.05 ft marks estimated to 0.01ft for 3-wire readings. All turning points crayon mark on concrete. Individual sight lengths were not all well balanced but overall sum of backsight distances exceeded foresights by only 52 ft in 1684 ft run.

Height above base of rail 0.8 ft.

[This entry was edited by Bill93 on Monday, June 29, 2009 at 8:15:12 AM.]

[Photos:]
photoMH0134_20051226_A.jpg

photoMH0134_20051226_M.jpg

photoMH0134_20051226_C.

photoLeveling equipment
(Not at field location)

Documented History (by the NGS)

01/01/1935 by CGS (MONUMENTED)
DESCRIBED BY COAST AND GEODETIC SURVEY 1935 AT ALBIA. AT ALBIA, MONROE COUNTY, ON THE CHICAGO, BURLINGTON AND QUINCY RAILROAD, 4 POLES WEST OF MILEPOST 304, AT THE CROSSING OF NORTH D STREET, 36 FEET WEST OF THE CENTERLINE OF THE STREET, 36 FEET SOUTH OF THE CENTERLINE OF THE MAIN TRACK, 4 FEET EAST OF A POLE, AND 2-1/2 FEET HIGHER THAN THE TRACK. A STANDARD DISK, STAMPED Y 11 1935 AND SET IN THE TOP OF A CONCRETE POST.

Control Text

  • The horizontal coordinates were scaled from a topographic map and have an estimated accuracy of +/- 6 seconds.
  • The orthometric height was determined by differential leveling and adjusted by the National Geodetic Survey in June 1991.
  • The geoid height was determined by GEOID99.
  • The dynamic height is computed by dividing the NAVD 88 geopotential number by the normal gravity value computed on the Geodetic Reference System of 1980 (GRS 80) ellipsoid at 45 degrees latitude (g = 980.6199 gals.).
  • The modeled gravity was interpolated from observed gravity values.

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