valleymetro2011straycurrentcorrosioncontrolsystemevaluation

2011 STRAY CURRENT

CORROSION CONTROL SYSTEM EVALUATION

CORROSION CONTROL EVALUATION 340160354 DOC 01 Page 1 of 14 Rev 1

2011 STRAY CURRENT CORROSION CONTROL SYSTEM EVALUATION

METRO LIGHT RAIL 605 S. 48TH STREET

PHOENIX, ARIZONA 85034

Submitted by

CCOORRRRPPRROO PPRROOJJEECCTT NNoo.. :: 334400116600335544 DDOOCC 11,, RREEVV 11

1 03/21/2012 Comments Incorporated E. Goldberg Sarvjit Singh

0 03/01/2012 Issued for Approval E. Goldberg Sarvjit Singh

REV DATE DD/MM/YY REMARKS PREPARED BY REVIEWED BY

Designation/ Project 2011 STRAY CURRENT CORROSION CONTROL EVALUATION

2011 STRAY CURRENT



TABLE OF CONTENTS

1.0 EXECUTIVE SUMMARY .................................................................................. 32.0 INTRODUCTION .............................................................................................. 53.0 CONCLUSIONS ................................................................................................. 7

3.1 STRAY CURRENT EXCHANGE BETWEEN METRO TRACKS AND EARTH .............................. 73.2 METRO TRACK-TO-EARTH RESISTANCE ...................................................................................... 73.3 METRO TRACK-TO-EARTH POTENTIALS ..................................................................................... 83.4 METRO YARDMAINLINE AND YARD-SHOP ELECTRICAL SEPARATION ............................ 83.5 SECTION 5.6 OF THE INTERGOVERNMENTAL AGREEMENT ................................................... 9

4.0 RECOMMENDATIONS ................................................................................... 115.0 DISCUSSION ..................................................................................................... 12

5.1 TRACK-TO-EARTH RESISTANCE .................................................................................................... 125.2 TRACK-TO-EARTH POTENTIAL ..................................................................................................... 125.3 STRAY CURRENT ................................................................................................................................ 12

6.0 TEST METHODS .............................................................................................. 136.1 TRACK-TO-EARTH RESISTANCE TESTS ....................................................................................... 136.2 TRACK-TO-EARTH POTENTIAL MEASUREMENTS AT SUBSTATIONS .................................. 136.3 PIPELINE POTENTIAL MONITORING .......................................................................................... 14

APPENDICES

APPENDIX - A .......................................................... Track-to-Earth Resistance Test Data

APPENDIX - B .............................................. Traction Power Substation Potential Graphs

APPENDIX - C ........................................................ Pipeline Test Station Potential Graphs

APPENDIX - D ....................................................... Aerial Imagery Maps of Test Locations

APPENDIX - E ........................................ Section 5.6 of the Intergovernmental Agreement

2011 STRAY CURRENT



1.0 EXECUTIVE SUMMARY

This report outlines the results of an evaluation of the in-service stray current corrosion control

system associated with Valley Metros direct current (DC) powered light rail transit system.

Consistent with Corrpros recommended scope of work, the field aspects of the evaluation

were completed between December 5th, 2011 and December 9th, 2011. The field testing

included:

Track-to-earth resistance measurements for the entire mainline and for the yard tracks.

Track-to-earth potential measurements at sub-stations. Utility structure-to-earth potential measurements at representative locations,

principally the City of Phoenix ductile iron water pipelines and South West Gas

pipelines.

The measured, normalized track-to-earth resistance ranges from 103.70 Ohms-1,000 feet of

single track (2 rails) to in excess of 1,000 Ohms-1,000 feet. The average normalized track-to-

earth resistance is approximately 306 Ohms-1,000 feet. The minimum acceptance resistance

criterion for embedded track under test was 100 Ohms-1000 feet track.

The comparison of test data between the previous years testing and the current testing

indicates no decay in the track-to-earth resistance of the mainline tracks.

Along the Metro Light Rail route, pipe-to-soil potential data was recorded for the following at

randomly selected test points: ten (10) water pipeline test points, two (2) South West Gas test

points, and one (1) reinforcing rebar test point. The pipeline test point data recorded do not

indicate detrimental interference effects on these selected pipelines. The very low level effects

measured are of the same scale as reported during the 2010 evaluation. It should be noted

that the pipe-to-soil potential logging was carried out on different pipes (not on previously

tested pipelines) along the entire route of the mainline tracks. This reinforces that there are no

signs of degradation of the mainline track electrical isolation characteristics. The magnitude

and time characteristics of the track-to-earth potentials are considered normal with no

indication of anomalous conditions that could impact stray current control.

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The total stray current exchange between the Metro mainline tracks and earth is estimated to

be less than 2 amperes. This level of stray current exchange is quite low, indicative of

effective stray current control. It is comparable to a low-output impressed current cathodic

protection system for a coated pipeline that is several miles long.

The track-to-earth potential logging data collected at the randomly selected TPSSs (traction

power substations) is normal. Present track-to-earth potential levels are considered typical

with no anomalous conditions indicated.

Recommendations derived from Corrpros evaluation include continued periodic surveillance.

The next step in this regard would be to develop a standard operating procedure (SOP). A

sufficiently detailed SOP is in order to establish a solid foundation for the stray current control

program and to assure consistency in the future; the SOP was incorporated during the 2011

testing and is being issued as a separate document.

2011 STRAY CURRENT



2.0 INTRODUCTION

This report presents results of Corrpros annual evaluation of in-service stray current corrosion

control for the Valley Metro light rail in Phoenix, Arizona. The system alignment is

approximately 21.5 miles long with 14 traction power sub-stations and 35 passenger station

platforms.

The stray current exchange between a direct current powered rail transit system and earth can

pose a risk of accelerated corrosion to the buried utility infrastructure as well as Metro

facilities. The Metro system includes state-of-the-art features that have been designed to

effectively control the level of stray current to practicable minimums. The primary design

measure is an electrically ungrounded traction power negative distribution system. This

includes the use of an electrically insulating rail boot for embedded mainline track-work

(predominant track type) and insulating rail fasteners for direct fixation track-work across two

bridges. While the stray current control measures are expected to be low maintenance, they

do require periodic monitoring to responsibly detect and correct anomalous conditions which

will undoubtedly occur from time to time as the system ages.

Prior to constructing the system, Metro entered into an intergovernmental agreement that

included Section 5.6 on corrosion control (The Agreement Sec. 5.6 is in Appendix E of this

report). The Agreement Sec. 5.6 stipulates that Metro will conduct stray current monitoring

and track-to-earth resistance tests on an annual basis. Track-to-earth resistances below 100

Ohms-1,000 feet (2 rails) for embedded track and 250 ohms-1,000 feet for direct fixation track

require corrective action based on the intergovernmental agreement page C-12.

The field aspects of Corrpros evaluation included:

Track-to-earth resistance measurements for the entire mainline and for the yard tracks.

Track-to-earth potential measurements at sub-stations. Utility structure-to-earth potential measurements at representative locations,

principally the City of Phoenix ductile iron water pipelines along with South West Gas

pipelines.

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The entire testing was carried out with full support from the support by the Valley Metro light

rail crew. All necessary work permits and access to various facilities was also provided and

obtained by the Valley Metro. Track-to-earth resistance testing was performed during non-

revenue hours of the train.

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3.0 CONCLUSIONS

3.1 STRAY CURRENT EXCHANGE BETWEEN METRO TRACKS AND EARTH

a) The calculated normal stray current exchange between the Metro mainline tracks and

earth is less than 2 amperes for the entire 21.5 miles.

b) Determined by the magnitude of stray current voltage, the level of stray current

exchange is quite low, indicative of effective stray current control. It is comparable to

a low-output impressed current cathodic protection system for a coated pipeline that is

several miles long.

c) The low-level stray current exchange between the Metro mainline tracks and earth is

considered consistent with design requirements.

d) The maximum average voltage change recorded for the utility test points was 20mV

and the minimum average voltage change recorded for the utility test points was

2.5mV; as depicted in Appendix C.

3.2 Metro Track-to-Earth Resistance

a) All other factors equal, the higher the track-to-earth resistance, the lower the level of stray current and resulting stray current corrosion impact on neighboring utilities and transit structures.

b) The measured, normalized track-to-earth resistance ranges from 103.70 Ohms-1,000 feet of single track (2 rails) to in excess of 1,000 Ohms-1,000 feet. The average normalized track-to-earth resistance for the mainline track is approximately 306 Ohms-1,000 feet. [From Appendix A: Mainline Track-to-Earth Resistance Average = (414.85 + 250.73 + 623.03 + 308.38 + 139.24 +103.70) 6 306 Ohms-1,000 feet.]

c) The calculated composite resistance-to-earth for the entire mainline track is

approximately on the order of 1.1419 Ohm. [From Appendix A: Mainline Measured Track-to-Earth Resistances in Parallel = 1 [(1/9.87) + (1/3.22) + (1/19.55) + (1/8.72) + (1/3.86) + (1/25.66)] 1.1419 Ohms.]

d) The measured mainline track-to-earth resistances are generally consistent with prior

data. They are in excess of the design and construction acceptance criterion of minimum 100 Ohms-1,000 feet for embedded track and minimum 250 Ohms-1,000 feet for ballasted and direct fixation track.

e) The mainline track-to-earth resistance testing revealed no direct track to ground

electrical contacts (shorts) or other anomalous conditions that could result in concentrated levels of high stray current exchange. Such conditions can occur,

2011 STRAY CURRENT



particularly with signaling circuits, switch machines, and along the direct fixation track on the Tempe Town Lake Bridge and over Interstate 10 (I-10). Periodic surveillance of the track-to-earth resistance allows for early detection and resolution of any stray current problems.

f) Corrpro carried out testing of the stray current control facilities between December 5th,

2011 and December 9th, 2011. Precipitation (rainfall) during 2011 was recorded approximately 1.41 inches based on the National Weather Service report. We did not observe any rain during the time period of testing. The impact of previous precipitation on track-to-earth resistance levels is not known. Based on statistics, the reported normal annual precipitation for Phoenix is approximately 0.99 inches. Stray current leakage levels typically increase during periods of precipitation and for some time thereafter.

g) Testing of the track-to-earth resistance is a straightforward process. It should be

considered Metros first line of defense for effective stray current control. Manual testing on an annual basis is the minimum requirement to comply with the intergovernmental agreement.

3.3 Metro Track-to-Earth Potentials

a) The maximum track-to-earth potentials range from negative -4.95 volts (rails accumulating stray current from earth in vicinity of measurement) to positive +4.0 volts (rails discharging stray current to earth in vicinity of measurement) during peak transit operating periods.

b) The magnitude and time characteristics of the track-to-earth potentials are considered normal with no indication of anomalous conditions that could impact stray current control.

3.4 Metro YardMainline and Yard-Shop Electrical Separation

a) By design, for stray current control, the yard traction power system is intended to be electrically separated from the mainline system under normal transit operations. Similarly, the yard traction power system is to be electrically separated from the shop system where the rails are grounded for electrical safety. The separation was found to be in place during Corrpros field evaluation.

b) Transit and railed maintenance vehicles that are parked across the yard/mainline rail insulating joints and or parked across the yard/shop rail insulating joints can cause excessive, unacceptable stray current levels because they electrically connect the different traction power electrification circuits. When the insulating joints are bridged, they can lower the effective resistance-to-earth of the mainline rail system and increase stray currents over extended distances.

c) The worst stray current corrosion conditions occur when the yard-shop insulating

joints are shorted concurrent with the yard-mainline insulating joints. Procedures need to be maintained at all times to avoid these conditions.

2011 STRAY CURRENT



d) The track-to-earth resistance measured in the yard 329.66 -1,000 ft.

e) Pipe-to-soil potentials were monitored at thirteen (13) representative locations along

the Valley Metro light rail tracks. Ten (10) of the test points were on ductile iron water lines that included corrosion control test stations and galvanic current cathodic protection (magnesium anodes). Two (2) test points were on South West Gas pipelines, and the other test point was a rebar test station for the concrete pad below the rail. The locations were selected to determine typical and expected worse-case conditions based on analyses of the track-to-earth resistance and track-to-earth potential data obtained during Corrpros field evaluation.

f) There are two predominant transit-influenced stray current effects influencing the

water lines. The most prevalent is caused by transit operations along the mainline. There is also a sporadic spike-type effect, which is believed to be associated with transit vehicles entering or leaving the yard and shorting the yard-mainline rail insulating joints. The spike-type effects are typically greater than those caused by the mainline operations. This same condition was observed in our previous evaluation in 2010 and 2009.

g) Average maximum transit-influenced pipe-to-soil potential variations caused by

mainline operations are typically less than 0.020 volt referenced to the quiescent potential that exists during non-revenue periods. The largest magnitude variation is 0.020 volt and occurs at the water line test point at 33.448073, 112.022441.

h) Average maximum spike-type changes in pipe-to-soil potential are typically less than 0.050 volt referenced to the quiescent potential that exists during non-revenue periods. The largest spike-type change is 0.125 volt, occurring at the water line test point at 33.446312, -111.970915.

i) While the pipe-to-soil potential data indicate Metro is having an electrical effect on the water lines, the effects are considered very low and do not present a corrosion threat. Pipe-to-soil potential variations caused by mainline transit operations that are consistently greater than 0.1 volt would typically warrant further evaluation relative to corrosion control significance. The measured effects are much lower than this threshold level.

j) The low-level stray current effects detected at the structures tested is considered to have very little impact on the operational reliability and service life of the utilities, provided there is no substantial increase and the utility cathodic protection is maintained.

3.5 Section 5.6 of the Intergovernmental Agreement

a) Corrpros evaluation of current conditions conforms to the breadth and intent of Section 5.6 of the intergovernmental agreement on corrosion control.

b) A program consisting of periodic track-to-earth resistance testing for the entire Valley Metro light rail system coupled with measurements at a sampling of utility monitoring points is the most responsive and cost-effective method for complying with the

2011 STRAY CURRENT



intergovernmental agreement. This proactive approach will also keep overall stray current levels to a practicable minimum.

2011 STRAY CURRENT



4.0 RECOMMENDATIONS

1. The information contained in this report should be conveyed to the City of Phoenix to comply

with the intergovernmental agreement. The information should also be conveyed to other

interested parties as appropriate.

2. Adhere to the written guidelines (SOP) for Valley Metros light rail system stray current

corrosion control maintenance and monitoring program as developed by Corrpro to assure

consistency in the future.

3. Conduct annual track-to-earth resistance tests as stated in the Intergovernmental Agreement

on Corrosion Control, Sec. 5.6. Track-to-earth resistances below 100 Ohms-1,000 feet (2 rails)

for embedded track and 250 ohms-1,000 feet for direct fixation track require corrective action

based on the agreement. Track-to-earth resistance testing should be considered Valley

Metros first line of defense for effective stray current control.

2011 STRAY CURRENT



5.0 DISCUSSION

5.1 Track-to-Earth Resistance

For this project, Corrpro measured the track-to-earth resistance. From Ohms law, increasing

track-to-earth resistance will decrease the amount of stray current exchange between the

traction power system and the earth.

Testing conducted during the 2011 survey indicates that the mainline track-to-earth

resistances are sufficient to satisfy the intergovernmental agreement for the mainline tracks

and effectively control stray current.

The track-to-earth test data and calculation sheets are provided in Appendix A.

5.2 Track-to-Earth Potential

Track-to-Earth Potential is used to estimate the amount of current exchange between the rail

tracks and the earth. Corrpro measured track-to-earth potentials at ten (10) traction power

substation locations along the alignment using Tinker & Rasor data loggers. Graphs of the

potentials recorded by the data loggers are provided in Appendix B.

5.3 Stray Current

Stray current, is current that travels along an unintended path, like traction power current

traveling through the earth to return to the substation via another route instead of along the

rails. As stray current moves through the earth it can be collected on and discharged from

buried metallic utilities. At locations of discharge from the metal structure, the electrical

potential of the structure will be made more positive; at these locations the risk of accelerated

corrosion is increased.

The electrical potential testing carried out by Corrpro indicates that the level of stray current is

minimal and there is a low risk of accelerated damage of buried utilities due to the Valley

Metros DC traction power systems.

2011 STRAY CURRENT



6.0 TEST METHODS

6.1 Track-to-Earth Resistance Tests

This is the primary field measurement used to gauge the in-service effectiveness of Metros

stray current corrosion control measures. If the track-to-earth resistance is maintained at a

relatively high level, the risk of the transit system causing stray current on nearby utilities can

be kept to a minimum.

a) For the survey, Corrpro measured track-to-earth resistances for the entire mainline system ( 21.5 miles) on a track section by track section basis, typically for dual track section lengths an average of 16,000 feet.

b) The tests were performed during non-revenue service, roughly 12:30 AM to 4:00 AM.

c) The tests were conducted while temporarily disconnecting impedance bond cables across certain rail insulating joints to sectionalize the rail network into approximate lengths of 16,000 feet.

d) The data sheets include a sketch of each test set up with locations of potential

measurements, connections for the applied current and locations of insulating joints.

e) A direct current (DC) test voltage of approximately 12-volts was impressed between the track section under test and an earth ground connection. The current output and DC voltage shift due to the applied current was measured and recorded simultaneously.

f) Cross-bonds, TPSS negative return and signal wire connections to the rails were left

connected during the testing of the mainline.

6.2 Track-to-Earth Potential Measurements at Substations

Concurrent with the pipeline potential monitoring, Corrpro used the battery-powered data

loggers to monitor track-to-earth potentials at ten (10) TPSSs. Using Ohms Law, the track-to-

earth potential data is used in conjunction with the track-to-earth resistance data to estimate

the magnitude and polarities of stray current exchange between the system rails and earth.

a) The data logger positive lead was connected to the track negative return and test common lead was connected to the building ground bus. Test connections were made safely with the traction power energized.

b) The monitoring period per substation was in excess of 12 hours and includes at least one morning and or one afternoon rush-hour period.

2011 STRAY CURRENT



6.3 Pipeline Potential Monitoring

Corrpro used battery-powered data loggers to monitor pipe-to-soil potentials at ten (10) water

pipeline test station locations and two (2) South West Gas pipeline test stations along the

Valley Metro light rail alignment. This data helps evaluate the effects of the stray current from

the rail on the nearby foreign structures.

a) Monitoring was performed typically in excess of 12 hours to cover at least one period of peak rail operation.

b) Measurements were also made at one power pole electrical ground rods. Experience shows data from the ground connections can often provide an overall indication of stray current effects in a given area.

c) Corrpro recorded the GPS coordinates (3 meter accuracy) for each of the utility test

points, traction power sub stations (TPSS), and catenary poles utilized during the potential monitoring and testing. The locations are shown on the satellite imagery sheets in Appendix - D.

END OF REPORT

2011 STRAY CURRENT

CORROSION CONTROL EVALUATION

CORROSION CONTROL EVALUATION 340160354 DOC 01 APPENDIX Rev 1

APPENDIX A

Track-to-Earth Resistance Test Data Table A1 Summary Table - Track-to-Earth Resistance Figure A1 Track-to-Earth Resistance vs. Location

Appendix A Reference Number Track-to-Earth Resistance

Field Data, Calculation Sheets and Sketches

1 Stn. 909+86 to 1119+93

2 Stn. 1119+93 to 1509+01

3 Stn. 1509+01 to 1668+34

4 Stn. 1668+34 to 1845+08

5 Stn. 1845+08 to 2025+10

6 Stn. 2025+10 to 2045+30

7 Stn. 4+00 to 28+00 (Yard Entrance)

8 Yard Lines

2011 STRAY CURRENT



Table A1 Summary Table - Track-to-Earth Resistance

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Notes

1 Dec. 08, 2011 909+86 1119+93 21,007 42,014 9.87 414.85 2 North end of Lines to Pierson St.

2 Dec. 08, 2011 1119+93 1509+01 38,908 77,816 3.22 250.73 2 Pierson St. to 27th St.

3 Dec. 07, 2011 1509+01 1668+34 15,933 31,866 19.55 623.03 2 27th St. to 51st St.

4 Dec. 06, 2011 1668+34 1845+08 17,674 35,348 8.72 308.38 2 51st St. to 6th St.

5 Dec. 05, 2011 1845+08 2025+10 18,002 36,004 3.86 139.24 2 6th St. to Dobson Rd.

6 Dec. 05, 2011 2025+10 2045+30 2,020 4,040 25.66 103.70 2 Dobson Rd. to E. End of Tracks

7 Dec. 09, 2011 4+00 28+00 1,200 2,400 629.13 1,509.93 0 Main Line to Yard Entrance Tracks

8 Dec. 09, 2011 28+00 - 13,500 27,000 12.20 329.66 2

Yard Track Testing

The yard includes combination of direct fixation and embedded tracks.

TOTAL 113,544 211,126 All in parallel : 1.1419 Miles 21.5

Average Normalized Track-to-Earth Resistance for entire Mainline system: 306.65 (-1,000FT)

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Track Station Number

Figure A1Track-to-Earth Resistance vs. Location

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13

Yard Entrance

T# - Traction Power Sub-Station Approximate LocationsYard Entrance at Stn 1647+25

100 ohm-1,000 FTMinimum for compliance with Intergovernmental Agreement

306 Ohm-1,000 FTAverage for entire Mainline

Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/8/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 45 FTime: 11:59 PMTest Location: North End of Line Voltmeter S/N: Starting Station 1119+93 Pierson St. Fluke 187V S/N 12850307Ending Station 909+86 End of Track Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 42,014 S/N 12850307Adder for Special Track (FT) - Other S/N

Current Voltage On Voltage Off Voltage DeltaCalculated Resistance

Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 1119+93Potential w.r.t. GRD for Catentary Pole 8.620 1.346 7.274 9.816Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole 0.618 0.288 -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole 8.640 1.263 7.377 9.955Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole 0.613 0.282 -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole 8.610 1.379 7.231 9.758Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole 0.622 0.292 -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole 8.610 1.343 7.267 9.807Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole 0.619 0.287 -Track-to-Earth @ (5) Stn No. 909+86Potential w.r.t. GRD for Catentary Pole 8.850 1.364 7.486 10.103Track-to-Earth @ (5a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (6)Potential w.r.t. GRD for Catentary Pole 8.720 1.362 7.358 9.930Track-to-Earth @ (6a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (7) Stn No.Potential w.r.t. GRD for Catentary Pole 8.650 1.360 7.290 9.838Track-to-Earth @ (7a)Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (8)Potential w.r.t. GRD for Catentary Pole 8.610 1.360 7.250 9.784Track-to-Earth @ (8a)Potential w.r.t. GRD for Catentary Pole - - - -

Average resistance measured 9.874

Test Location

0.741

Test Location North End of Line Page 2 of 2Starting Station 1119+93 Date: 12/8/2011

Estimated Track Length (including

Special Track)

Average Change

(V)

Current Applied (Amps.)

Measured Resistance

()1119+93 909+86 42,014 7.317 0.741 9.87398785

Sketch/Calculations:Notes:

1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track

Voltage Applied with a timed interupter switch.The current measured using calibrated Shunt.Located at Station: 1119+93

Normalized Track-to-Earth Resistance (-1,000 Ft. of

Single Track)414.85

Start and End Station No.

egoldbergText Box*Calculation Note: [Average Voltage Change (V) Current Applied (Amps.)] (Estimated Track Length 1,000)= Normalized Track-to-Earth Resistance (-1,000 Ft. of Single Track)

Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/8/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 45 FTime: 11:59 PMTest Location North End of Line Voltmeter S/N: Starting Station 1119+93 Pierson St. Fluke 187V S/N 12850307Ending Station 1509+01 27th St. Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 77,816 S/N 12850307Adder for Special Track (FT) - Other S/N


Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 1119+93Potential w.r.t. GRD for Catentary Pole 5.913 1.450 4.463 3.404Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole 1.329 2.160 -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole 5.886 1.446 4.440 3.387Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole 1.355 2.187 -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole 5.863 1.485 4.378 3.339Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole 1.357 2.412 -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole 5.879 1.495 4.384 3.344Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole 1.385 2.258 -Track-to-Earth @ (5) Stn No. 1509+01Potential w.r.t. GRD for Catentary Pole 5.632 1.900 3.732 2.847Track-to-Earth @ (5a) Stn No.Potential w.r.t. GRD for Catentary Pole 0.500 0.450 - -Track-to-Earth @ (6)Potential w.r.t. GRD for Catentary Pole 5.649 1.901 3.748 2.859Track-to-Earth @ (6a) Stn No.Potential w.r.t. GRD for Catentary Pole 0.480 0.465 - -Track-to-Earth @ (7) Stn No.Potential w.r.t. GRD for Catentary Pole 5.658 1.390 4.268 3.256Track-to-Earth @ (7a)Potential w.r.t. GRD for Catentary Pole 0.476 0.726 - -Track-to-Earth @ (8)Potential w.r.t. GRD for Catentary Pole 5.660 1.280 4.380 3.341Track-to-Earth @ (8a)Potential w.r.t. GRD for Catentary Pole 0.801 0.780 - -


Test Location

1.311

Test Location North End of Line Page 2 of 2Starting Station 1119+93 Date: 12/8/2011

Estimated Track Length (including

Special Track)

Average Change

(V)


Measured Resistance

()1119+93 1509+01 77,816 4.224 1.311 3.22206331


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)250.73


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/7/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 46 FTime: 11:59 PMTest Location Voltmeter S/N: Starting Station 1509+01 27th St. Fluke 187V S/N 12850307Ending Station 1668+34 51st St. Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 31,866 S/N 12850307Adder for Special Track (FT) - Other S/N




Test Location

0.374

Test Location Page 2 of 2Starting Station 1509+01 Date: 12/7/2011

Estimated Track Length

(including Special Track)

Average Change (V)


Measured Resistance

()1509+01 1668+34 31,866 7.312 0.374 19.5515374


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)623.03


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/6/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 44 FTime: 11:59 PMTest Location Voltmeter S/N: Starting Station 1668+34 51st St. Fluke 187V S/N 12850307Ending Station 1845+08 E. 6th St. Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 35,348 S/N 12850307Adder for Special Track (FT) - Other S/N




Test Location

0.460

Test Location Page 2 of 2Starting Station 1668+34 Date: 12/6/2011



Average Change (V)


Measured Resistance

()1668+34 1845+08 35,348 4.013 0.460 8.72418478


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)308.38


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/5/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 40 FTime: 11:59 PMTest Location East End of Line Voltmeter S/N: Starting Station 2025+10 Dobson Rd. Fluke 187V S/N 12850307Ending Station 1845+08 E. 6th St. Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 36,004 S/N 12850307Adder for Special Track (FT) - Other S/N


Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 2025+10Potential w.r.t. GRD for Catentary Pole -2.287 1.413 3.700 3.811Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole 0.437 0.570 -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole -2.305 1.416 3.721 3.832Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole 0.444 0.568 -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole -2.289 1.415 3.704 3.815Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole 0.440 0.565 -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole -2.310 1.419 3.729 3.840Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole 0.440 0.573 -Track-to-Earth @ (5) Stn No. 1845+08Potential w.r.t. GRD for Catentary Pole -2.601 1.201 3.802 3.916Track-to-Earth @ (5a) Stn No.Potential w.r.t. GRD for Catentary Pole 0.512 0.623 - -Track-to-Earth @ (6)Potential w.r.t. GRD for Catentary Pole -2.598 1.189 3.787 3.900Track-to-Earth @ (6a) Stn No.Potential w.r.t. GRD for Catentary Pole 0.512 0.619 - -Track-to-Earth @ (7) Stn No.Potential w.r.t. GRD for Catentary Pole -2.605 1.195 3.800 3.913Track-to-Earth @ (7a)Potential w.r.t. GRD for Catentary Pole 0.509 0.621 - -Track-to-Earth @ (8)Potential w.r.t. GRD for Catentary Pole -2.599 1.199 3.798 3.911Track-to-Earth @ (8a)Potential w.r.t. GRD for Catentary Pole 0.512 0.622 - -


Test Location

0.971

Test Location East End of Line Page 2 of 2Starting Station 2025+10 Date: 12/5/2011



Average Change (V)


Measured Resistance

()2025+10 1845+08 36,004 3.755 0.971 3.867276


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)139.24


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/5/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 40 FTime: 11:59 PMTest Location East End of Line Voltmeter S/N: Starting Station 2025+10 Dobson Rd. Fluke 187V S/N 12850307Ending Station 2045+30 E. End of Tracks Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 4,040 S/N 12850307Adder for Special Track (FT) - Other S/N


Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 2025+10Potential w.r.t. GRD for Catentary Pole 9.520 2.380 7.140 26.642Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole 0.502 0.609 -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole 9.531 2.400 7.131 26.608Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole 0.516 0.600 -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole 9.610 2.460 7.150 26.679Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole 0.512 0.613 -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole 9.621 2.462 7.159 26.713Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole 0.532 0.589 -Track-to-Earth @ (5) Stn No. 2045+30Potential w.r.t. GRD for Catentary Pole 9.740 3.250 6.490 24.216Track-to-Earth @ (5a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (6)Potential w.r.t. GRD for Catentary Pole 9.780 3.125 6.655 24.832Track-to-Earth @ (6a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (7) Stn No.Potential w.r.t. GRD for Catentary Pole 9.810 3.117 6.693 24.974Track-to-Earth @ (7a)Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (8)Potential w.r.t. GRD for Catentary Pole 9.790 3.175 6.615 24.683Track-to-Earth @ (8a)Potential w.r.t. GRD for Catentary Pole - - - -


Test Location

0.268

Test Location East End of Line Page 2 of 2Starting Station 2025+10 Date: 12/5/2011



Average Change (V)


Measured Resistance

()2025+10 2045+30 4,040 6.879 0.268 25.6683769


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)103.70


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/9/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 55 FTime: 8:00 AMTest Location Yard Testing Voltmeter S/N: Starting Station 4+00 Main Line Entrance Fluke 187V S/N 12850307Ending Station 28+00 Yard Entrance Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 2,400 S/N 12850307Adder for Special Track (FT) - Other S/N


Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 4+00Potential w.r.t. GRD for Catentary Pole 13.150 0.490 12.660 633.000Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole 13.150 0.556 12.594 629.700Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole 13.130 0.450 12.680 634.000Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole 13.150 0.420 12.730 636.500Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole -Track-to-Earth @ (5) Stn No. 28+00Potential w.r.t. GRD for Catentary Pole 12.510 0.020 12.490 624.500Track-to-Earth @ (5a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (6)Potential w.r.t. GRD for Catentary Pole 12.510 0.019 12.491 624.550Track-to-Earth @ (6a) Stn No.Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (7) Stn No.Potential w.r.t. GRD for Catentary Pole 12.530 0.024 12.506 625.300Track-to-Earth @ (7a)Potential w.r.t. GRD for Catentary Pole - - - -Track-to-Earth @ (8)Potential w.r.t. GRD for Catentary Pole 12.530 0.019 12.511 625.550Track-to-Earth @ (8a)Potential w.r.t. GRD for Catentary Pole - - - -


Test Location

0.020

Test Location Yard Testing Page 2 of 2Starting Station 004+00 Date: 12/9/2011



Average Change (V)


Measured Resistance

()4+00 28+00 2,400 12.583 0.020 629.1375


1a 1 5 5a

2a 2 6 6a WB track

3a 3 7 7a

4a 4 8 8a EB track




Single Track)1509.93


Track-to-Earth Resistance TestsTrack Section Using Current Drop Method Page 1 of 2Engineer: Ed Goldberg Project Desc.:Technician: Mike Beebe Track-to-Earth Resistance TestingDate: 12/9/2011Client: Metro Light Rail - Pheonix, AZ Weather/Notes:Job #: 340160354 Clear 55 FTime: 8:00 AMTest Location Yard Testing Voltmeter S/N: Starting Station 28+00 Yard Entrance Fluke 187V S/N 12850307Ending Station - Ammeter S/N:Test 1 or 2 track directions 2 Fluke with 0.01 ohm wire shuntTrack Length (FT) 27,000 Total Estimated S/N 12850307Adder for Special Track (FT) - Other S/N


Quantity Units, V, mV, Ohms Amps. Vdc Vdc Vdc Track-to-Earth @ (1) Stn No. 28+00Potential w.r.t. GRD for Catentary Pole 3.350 0.121 3.229 12.231Track-to-Earth @ (1a) Potential w.r.t. GRD for Catentary Pole 0.518 0.647 -Track-to-Earth @ (2)Potential w.r.t. GRD for Catentary Pole 3.347 0.128 3.219 12.193Track-to-Earth @ (2a) Potential w.r.t. GRD for Catentary Pole 0.518 0.652 -Track-to-Earth @ (3) Stn No.Potential w.r.t. GRD for Catentary Pole 3.352 0.125 3.227 12.223Track-to-Earth @ (3a) Potential w.r.t. GRD for Catentary Pole 0.515 0.632 -Track-to-Earth @ (4)Potential w.r.t. GRD for Catentary Pole 3.345 0.120 3.225 12.216Track-to-Earth @ (4a) Potential w.r.t. GRD for Catentary Pole 0.512 0.648 -Track-to-Earth @ (5) Stn No. Inside YardPotential w.r.t. GRD for Catentary Pole 3.349 0.132 3.217 12.186Track-to-Earth @ (6) Inside YardPotential w.r.t. GRD for Catentary Pole 3.352 0.127 3.225 -Track-to-Earth @ (7) Stn No. Inside YardPotential w.r.t. GRD for Catentary Pole 3.351 0.128 3.223 12.208Track-to-Earth @ (8) Inside YardPotential w.r.t. GRD for Catentary Pole 3.349 0.130 3.219 -

Average resistance measured 12.210 Test Location Yard Testing Page 2 of 2Starting Station 028+00 Date: 12/9/2011



Average Change (V)


Measured Resistance

()28+00 - 27,000 3.223 0.264 12.209596



Test Location

0.264



Single Track)329.66


2011 STRAY CURRENT



APPENDIX B

Traction Power Substation Potential Graphs Table B1: Summary Table - Track-to-Earth Potential Datalogs Table B2: Summary Table - Estimated Current Exchange between Track and Earth Figure B1: Data Logger Locations and Structure Type versus Location Figure B2: Track-to-Earth Potential Figure B3: Stray Current Exchange

Track-to-Earth Potential Traces

Appendix B Reference Number

Location ID Stn. No.

1 TPSS#1 1003+50

2 TPSS#2 1051+25

3 TPSS#5 1301+50

4 TPSS#7 1496+25

5 TPSS#8 1578+20

6 TPSS#9 1693+50

7 TPSS#10 1787+15

8 TPSS#12 1925+00

9 TPSS#13 1996+90

10 TPSS#14 2037+50

Note: All measurements made using utility bond bus connection and substation grounding connection inside the traction power sub-station buildings for above locations.

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Figure B1 - Data Logger Locations and Structure Type versus Location

Waterline-to-Earth Potential

South West Gas-to-Earth Potential

Track-to-Earth Potential

T1 T2 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13 T14

Yard Entrance

egoldbergText BoxTPSS Location

2011 STRAY CURRENT



Table B1 - Summary Table - Track-to-Earth Potential Datalogs

Quiescent Magnitude:

Non-Revenue

Hours (Volts)

Average Maximum Potential (Volt w.r.t. Ground Bus)

Location ID Stn. No. Positive (Rails Discharging

Stray Current)

Negative (Rails Accumulating Stray Current)

TPSS#1 1003+50 -1.50 2.25 -4

TPSS#2 1051+25 -0.50 1.50 -4.85

TPSS#5 1301+50 -0.50 2.40 -0.45

TPSS#7 1496+25 -1.00 1.95 -3

TPSS#8 1578+20 -1.00 4.00 -4.25

TPSS#9 1693+50 -1.50 0.95 -3.5

TPSS#10 1787+15 -1.00 2.25 -4.75

TPSS#12 1925+00 -1.50 2.00 -4.75

TPSS#13 1996+90 -1.50 3.00 -4.75

TPSS#14 2037+50 -1.00 2.00 -4.95

*No testing was done at TPSS: 3, 4, 6, and 11

*Potentials are all with respect to electrical ground

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Figure B2 - Track-to-Earth Potential

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13

RED line: Average Maximum Positive Track-to-Earth Potential(Rails Discharging Stray Current)

Black line: Average Maximum Negative Track-to-Earth Potential(Rails Accumulating Stray Current) Yard Entrance

2011 STRAY CURRENT



Table B2 - Summary Table Calculated Current Exchange

Between Track and Earth

Average Maximum Stray Current Exchange (mA per 1000 ft of track

system)

Location ID Stn. No. From Track to Earth

From Earth to Track

TPSS#1 1003+50 10.8 -19.3

TPSS#2 1051+25 12.0 -38.6

TPSS#5 1301+50 19.1 -3.6

TPSS#7 1496+25 15.5 -23.9

TPSS#8 1578+20 12.8 -13.6

TPSS#9 1693+50 6.2 -22.7

TPSS#10 1787+15 14.6 -30.8

TPSS#12 1925+00 28.8 -68.3

TPSS#13 1996+90 43.2 -68.3

TPSS#14 2037+50 38.5 -95.2

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Figure B3 - Stray Current Exchange

T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 T13

RED line: Average Maximum Stray Current From Track to Earth

Black line: Average Maximum Stray Current From Earth to Track

Yard Entrance

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AC/DC Unfiltered

Unit: Tinker & Rasor s/n: 03138-E20 File: Config.dlg 12/7/2011 4:23:03 AM

egoldbergText BoxSubstation 1Latitude, Longitude: 33.517680, -112.098807

egoldbergText BoxDC Voltage

egoldbergLine

egoldbergLine

egoldbergText BoxDates Data was Recorded: 12/07/11 to 12/09/12

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Unit: Tinker & Rasor s/n: 02244-05102-E20 File: Config.dlg 12/7/2011 4:17:17 AM



egoldbergLine

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Unit: Tinker & Rasor s/n: 03138-E20 File: Config.dlg 12/6/2011 5:26:05 PM



egoldbergLine

egoldbergLine


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Unit: Tinker & Rasor s/n: 03173-E20 File: Config(1).dlg 12/6/2011 6:16:59 PM



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Unit: Tinker & Rasor s/n: 02244-05102-E20 File: Config(1).dlg 12/6/2011 5:05:00 PM



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Unit: Data Logger s/n: 02811-E20 File: Config(1).dlg 12/6/2011 5:46:09 PM



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Unit: Tinker & Rasor s/n: 02244-05102-E20 File: Sub Station 12 12-5-11 to 12-6-11.dlg 12/5/2011 11:01:34 PM



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10

15

Time (Minutes)

AC/DC Unfiltered




egoldbergLine

egoldbergLine


-25

-20

-15

-10

-5

0

5

10

-25

-20

-15

-10

-5

0

5

10

Time (Minutes)

AC/DC Unfiltered

Unit: Data Logger s/n: 02811-E20 File: Config.dlg 12/6/2011 12:36:16 AM



egoldbergLine

egoldbergLine


2011 STRAY CURRENT



APPENDIX C

Utility Potential Traces and Other Utility Data

Thirteen Datalog Traces of Utility Potential Versus Time

Appendix C Reference Number

Structure Latitude Longitude Reference Appendix

D Page

1 Fire Hydrant 33.446312 111.970915 62 South West Gas 33.438035 111.946918 93 Rebar 33.439816 111.950642 94 South West Gas 33.446290 111.970724 65 Fire Hydrant 33.483312 112.073652 26 Waterline 33.448094 112.024303 47 Fire Hydrant 33.482397 112.073641 28 Fire Hydrant 33.483758 112.073664 29 Waterline 33.448075 112.023642 4

10 Fire Hydrant 33.448079 112.024780 411 Fire Hydrant 33.448073 112.022441 412 Fire Hydrant 33.483218 112.073666 213 Fire Hydrant 33.481940 112.073619 2

*Dateformatofdatalogging:Year/Month/Day*Timeformatofdatalogging:24hrClock

WashingtonStreetFireHydrantTestStation

(Latitude,Longitude:33.446312,111.970915)


egoldbergText BoxTime


WashingtonStreetSouthWestGasTestStation(Latitude,Longitude:33.438035,111.946918)




DataLoggerinMedianatParksideDriveRebarTestStation





WashingtonStreetSouthWestGasTestStation(Latitude,Longitude:33.446290,111.970724)




N.CentralAve.FireHydrantTestStation





E.WashingtonStreetWaterTestStation





N.CentralAve.FireHydrantTestStation(Latitude,Longitude:33.483758,112.073664)




E.WashingtonStreetWaterTestStation





E.WashingtonStreetFireHydrantTestStation(Latitude,Longitude:33.448079,112.024780)




E.WashingtonStreetFireHydrantTestStation(Latitude,Longitude:33.448073,112.022441)




N.CentralAve.&E.CatalinaDr.FireHydrantTestStation




2011 STRAY CURRENT



APPENDIX D

Aerial Imagery Maps of Test Locations

egoldbergText BoxAppendix - DPage # 1

2011 STRAY CURRENT



APPENDIX E

Section 5.6 of the Intergovernmental Agreement

Table of Contents1.0 Executive Summary2.0 Introduction3.0 Conclusions4.0 Recommendations5.0 Discussion6.0 Test MethodsAppendix - AAppendix - BAppendix - CAppendix - DAppendix - E

valleymetro2011straycurrentcorrosioncontrolsystemevaluation

Documents

earth potential measurements

earth potentials

stray current exchange

earth resistance tests

metro yardmainline

metro tracks

appendices appendix

pipeline potential monitoring