Stray Current Control of Direct Current-Powered Rail Transit Systems: A Guidebook (2020)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

85 Summary of Agency Response Findings A P P E N D I X D

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 1 Transit Agency Name, Contact Person Name, and Title 2 Any special weather condition criteria or design requirement? For example, special concrete additives, switch heating units, reduced service, different seasonal track-to-earth resistances, etc. Special Cold weather measures. Corrosion issues due to melting of ice. Hot and Humid weather. There are times with limited and/or no service due to heavy rains and poor drainage. No special criteria No special criteria 3 How old is the transit system? (which year was it put in service?) 23 - Years (In service since 1994 with various new routes since then) 13 - Years (In service since 2004 with various routes since the initial start) 27 - Years (In service since 1990 with various new routes since then) 113 - Years (In service since 1904 with various routes since the initial start) 4 What is the length of the total system (provide breakdown by system type)? 48 miles of LRT 7.5 miles of LRT 88 miles of LRT and 22.5 miles of HRT 660 miles of LRT 5 What is the type, size, and cross- section of the rail used? Provide sketches along with your response if available. 115RE 115RE, Ri59/13 115RE, Ri59/13, and Ri52 6 Number of substations and break down by service line Total = 8 Total = 120 Total = 214 7 What is the average spacing of the substations? > 1 but < 2 miles > 1 but < 2 miles > 1 but < 1.5 miles (depends on the configuration necessary) > 1 but < 1.25 miles 8 What is largest spacing between the two substations? > 1.5 mile < 2 miles < 1.5 miles < 1.25 miles 9 What is the spacing between the substations and passenger stations, if any? mostly at the same location mostly at the same location No correlation 1 to 1.25 miles

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 10 What tests were conducted in the baseline survey (pre-revenue service testing)? Which of those tests were recommended for future maintenance testing? Baseline testing is conducted on the newer lines No baseline testing was done on the older line(s) before revenue service. However, the tests were conducted immediately after the revenue service. The tests were also carried out on the lines currently under construction No baseline testing was done on the older lines. The goal is to conduct baseline testing before revenue service on the lines currently under construction Not sure 11 What guidelines/standards (both national and international) were followed for the baseline survey? Transit agency design, criteria and ASTM standard Transit agency design, criteria, ASTM standard, NACE - Peabody and Cathodic Protection Survey Procedures Consultant is currently in the process of developing a criteria document for the transit agency N/A 12 What were the limiting values identified for track-to-earth resistance during the baseline survey? 250 ohms/1000 track feet 250 ohms/1000 track feet 300 ohms/1000 track feet - Embedded track 500 ohms/1000 track feet - Ballasted track 13 What were the limiting values identified for track-to-earth resistance during subsequent maintenance tests? 250 ohms/1000 track feet 250 ohms/1000 track feet Track-to-earth measurements are not part of regular scheduled maintenance. 5 ohms/1000 track feet 14 What design measures were incorporated to reduce stray current corrosion? LRT Design Criteria followed Rebar system within the track slab, continuous welded rail, insulated pads, cross bonding, and rail boot Sacrificial anodes, insulated pads and direct fixation. Cross bonds installation Continuously welded rail, non grounded system

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 15 What other design provisions are incorporated to control stray current leakage? Extruded rubber on both sides Bathtub membrane in the special track work sections. Active and Passive Method- insulated plates and fasteners, rail boot Insulated Pads 16 Is there a program for track maintenance? If yes, what is it? Transit agency design criteria requirements are followed Yes, visual inspections are conducted. Transit agency also has a maintenance manual that the staff follows Yes, visual inspections are conducted Yes, visual inspections are conducted 17 Do you routinely perform stray current control testing/monitoring for operating sections of your rail systems? No, unless a stray current problem is suspected or reported Yes regular testing of the tracks is carried out by Consultant along with visual monitoring by transit agency staff No there is no routine program for testing or monitoring. Currently working on getting one. No, unless a stray current problem is suspected or reported 18 Do you have written procedures for your stray current control testing, monitoring and maintenance? If yes, please send a copy with this response. No, but there is a design criteria manual No, but there is a design criteria manual. Additionally, consultant follows a standard testing plan that has been carried out for years now Didn’t have any monitoring and/or maintenance program in the past. Currently working on developing one No, The stray current leaks are detected and reported by utility providers and other third parties.but there is a design criteria manual 19 Is track-to-earth resistance measured as part of the testing/maintenance plan? LRT design criteria followed LRT design criteria followed oNoN 20 What is the track-to-earth resistance for the system currently? Please breakdown by service line if there is a difference. Should be: 250 ohms/1000 track feet Equal to and/or above the limited resistance as defined above Not measured for all lines. However, one of the newer lines was recently measured at 250 ohms/1000 feet of track N/A

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 21 Can stray current corrosion be differentiated from other corrosions to the metal structures for your system? seYseYseYseY 22 Have you encountered stray current corrosion-related problems on the system? If yes, how so? Yes - Hand rails on the high bars corrode No - Control and mitigation measures are keeping stray current under control Yes - we receive notification from the utility owners and other third parties Yes - reported by utility companies in the vicinity of the transit system 23 Who is responsible (entity) for the stray current corrosion control, maintenance, testing and monitoring? Engineering and Track Maintenance Department Engineering and Track Maintenance Department along with the help of corrosion consultant Engineering and Track Maintenance Department Transit agency is responsible once the problem is reported 24 Do neighboring utilities currently believe they are experiencing transit caused stray current effects? Yes, however, things are under control Yes, however, things are under control Yes, however, things are under control Yes, however, things are under control 25 When was the first stray current corrosion related problem noticed? When was it repaired? Don’t know the initial occurrence but, hand rails on the high bars corroded No problems found. Track slab rebar system is very efficient in keeping the stray current contained as designed. Don’t have any program. Now dealing with the problems as they arise. Utilities started the testing and complained about Stray current on their lines Visually found during the track survey, don’t remember the date - ongoing issue has been the failure of lead cable. 26 What measures were taken to control and/or remove the stray current corrosion issues? Used Steel handrails and replaced the concrete in which the hand rails were embedded Regular testing informs transit agency about any problems - Testing done every 3 years Testing and maintenance work is in process on some select lines Lead cables were replaced 27 How long the repairs have been going on? Regular maintenance repairs are carried out on need basis Regular maintenance repairs are carried out on need basis N/A It’s an ongoing task, depending on complains 28 Is historical corrosion and repair data available? Can it be reviewed? Confidential Not available Not available No 29 Is there a log of maintenance conducted to address the stray current corrosion? oNoNoNoN

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 30 Is there a log of total cost of the corrosion repairs to-date? Can it be reviewed? oNoNoNoN 31 Currently, are there any stray current corrosion problems? seYseYoNseY 32 Have stray current corrosion issues caused to modify the maintenance plan or stray current control methodology? Can the plan be reviewed? A/NoNoNseY 33 Has the present stray current corrosion problem been repaired/fixed? Yes (E-clips replacement project) Corrosion consultant is currently conducting the survey and will address the issue if any Corrosion consultant is currently conducting the survey and addressing the issues. Yes Cost 34 What was the total cost for the most recent stray current corrosion repair? Don’t have that detail (the E-clips replacement project was $600K) Don’t know - Corrosion consultant performs the repair work if required Corrosion consultant has been hired to access the magnitude of repair work required Don’t know 35 How many stray current corrosion repairs are typically made per year? wonkt’noDA/NA/Nwonkt’noD 36 Has the frequency of stray current corrosion related problems decreased or increased with time? With the mitigation of current issues we are expecting the corrosion to decrease No change The problem accumulated for the last many years and are surfacing now. In general the frequency has increased The frequency has decreased however, being an older system issues come up on regular basis 37 How many route miles of light or heavy rail are currently under construction and/or planned over the next few years? Don’t know 10+ miles of LRT Don’t know Don’t know 38 For in-progress transit construction and/or planned extensions over the next few years (if any), what stray current control provisions are expected and/or engaged? All new construction to follow the guidance provided in the transit agency design criteria manual Isolating pads under rails and fasteners, rail on top of concrete slab, cross bonding, and track slab rebar system Isolating pads under rails and fasteners, rail on top of concrete slab or ties, Sacrificial anodes, and cross bonding Structure stray current drainage, Ungrounded negative return circuit, rail isolation, utility relocation and protection

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 39 What is the latest total annual operating cost for the rail system? $30 million (maintenance and operation) Confidential Information Confidential Information Confidential Information 40 What part of the total operating cost is for non-vehicle maintenance? $5 million Confidential Information Confidential Information Confidential Information 41 What is the estimated annual cost for stray current corrosion repairs excluding the consultant fee? $0 (the cost is covered through additional grant money) Don’t know Don’t know, this will be the first year Confidential Information 42 What do you estimate the repair costs due to stray current corrosion to be for the next 5 years? Don’t know Don’t know Don’t know Don’t know 43 What percentage of this cost will be the consultant fee? ~$250K for periodic maintenance and testing Don’t know Don’t know 44 Is there a certain budget to address the on-going stray current corrosion issues? No Didn’t have any program so there was no budget. No 45 Is the transit system still in need of any repair/mitigation to control the stray current issues? Yes The only recurring cost is the regular testing and maintenance conducted by the consultant seYseY Summary 46 “Lessons learned” from the stray current corrosion incidents and/or repairs? Regular inspections and testing is necessary to avoid major failures. Do not embed the track and if embedded ensure that rail is well insulated and is on dedicated ROW Regular inspections and testing is necessary to avoid major failures. Maintenance plan, Guidance and Standards needed, man power, funding for the repairs. 47 What changes or modifications other than above lessons learned would you like to see or recommend to the industry? National Standards and Guidance manuals Guidance and Standards needed to maintain the tracks Maintenance plan, Guidance and Standards needed to maintain the tracks

S. No. Question Transit Agency Name Transit Agency 1 Transit Agency 2 Transit Agency 3 Transit Agency 4 48 Is there a local electrolysis committee to discuss stray current issues? seYseYseYseY 49 Do you participate in the local committee? seYseYoNseY 50 What stray current design specifications or manuals have been the most helpful in the past? Which ones have guided your design and maintenance methodology? Transit agency design criteria NACE and IEEE standards NACE and IEEE standards Transit agency design criteria 51 Do any Federal guidelines impact your design and maintenance approaches? Are there any that have a negative impact? oNoNoNoN

S. No. 1 2 3 4 5 6 7 8 9 Transit Agency 5 Transit Agency 6 Transit Agency 7 Transit Agency 8 Transit Agency 9 Design criteria includes provisions for switch heaters Hot and foggy climates, wider track gauge Snow and ice conditions, so we use hot air blowers, pan heaters, cal-rod heaters, and 3rd rail deicing cables powered by our dc traction power. No concrete in these areas. During winter there are periods below the freezing point and therefore de-icing salt is applied to roadways and point heating units are installed. Coastal environment, different conditions in autumn and winter. 31 - Years (In service since 1986 with various new routes since then) 45 - Years (In service since 1972 with various new routes since then) 59 - Years (with various new routes since then) 20 - Years (with various routes since then) 10 - Years (with various routes since then) 60 miles of LRT 110 miles of LRT(double track) 189 miles of LRT, 42 miles of HRT 43 miles of LRT 20 miles of LRT (double track) 115RE, Ri59/13, and Ri52 AREMA 119RE Subway: 100ARA-A (old) and 115RE (new and replacement rail). Street car: 115lb head hardened Ballasted sections: 113lb, Raised or slab track construction: 80lb, Embedded rail: Corus rail 59R2 type coated rail / Corus Rail 35GP rail Standard 54EI (previously named UIC54) Total = 52 Total = 66 (including street car stations) Total = 30 < 1 mile > 1 but < 2 miles (withfew longer sections) > 1 but < 2 miles > 1 but < 2 miles (with one longer than 2 mile section) > 1 but < 2 miles Slightly > 1 mile slightly > 2.2 miles < 2 miles (slightly > 5.5 miles on Streetcar) slightly > 2.7 miles No correlation Some are on same location whereas others vary Most substations are close to stops Same location Response from Transit Agencies Total = 62 0 to up to .43 miles slightly < 2 miles Total = 19

S. No. 10 11 12 13 14 Transit Agency 5 Transit Agency 7 Transit Agency 8 Transit Agency 9 Response from Transit Agencies Track isolation testing includes rail boot holiday test, rail-to-earth and rail-to-rail resistance testing. Also, pipe-to-earth potential measurements are taken on selected underground utilities that cross, or are adjacent to the ROW. On elevated structures, baseline rail-to-rebar, rail-to-earth, and rebar to-earth potential measurements, and collector mat to earth current measurements are taken. Not Sure The standard is to have baseline stray current studies done prior to and after a subway line is in service. No baseline testing was done on the older lines. Only track-to-earth resistance testing is conducted as part of maintenance testing During construction rail-to-earth resistance values are recorded. Monitoring is undertaken at selected locations on third party utility assets at risk of stray current corrosion. Monitoring includes logging of corrosion potential of the asset and current flow in accessible bonding straps. The conductance per unit length is calculated as the length of the track section is known. ASTM: C0876, D257-91, and G165. NACE: RP0104, RP0169, RP0188, RP0274, RP0572, TM0497, and TR35201. ASM Handbook, volume 13C. NACE: Peabody's and Cathodic Protection Survey Procedures Transit agency design standard None are listed in the baseline surveys. For the track-to-earth resistance tests, transit agency standard is 250 ohm/km. EN 50122-2, EN 50162, Office of the Rail Regulator Tramway Technical Guidance Note No. 3 – Stray Current Design EN 50122-1, -2 and -3, European Standard, Railway applications- Fixed installations – Electrical safety, earthing and return circuit: Part1, Part2, Part3 200 ohms/1000 track feet - Embedded track 500 ohms/1000 track feet - DF and Ballasted track 500 ohms/1000 track feet .01 ohms/km to an average of 36 ohm/km. varies for different lines Between 5 to 20 ohm-km (single rail) As per EN 50122-2, conductance per unit length for a single track is 0.5 S/km Track-to-earth measurements are not part of regular scheduled maintenance. N/A .02 ohms/km to an average of 27 ohm/km. varies for different lines 20 ohm km (single rail) - only where the construction value met or exceeded this As per EN 50122-2 the recommended conductance per unit length for a single track is 0.5 S/km Rail isolation; including rail boot, bath tub construction for turnouts. For DF and ballasted tracks use of insulating pads and fasteners. Use of HDPE instead of ductile iron, casings, IJS, anode beds, impressed current, and test stations for utilities Insulated rail pads, Negative grounding devices, Substation spacing. Cross bonding Insulated pads, rail clips, impedance bonds, cross bonding to name a few Minimize leakage at source by maintaining a high level of rail to earth resistance and low return circuit resistance; this is combined with a stray current collection system in the street running sections to collect a high proportion of any current that does leak. Isolated track constructions, short distances between substations, dimension of return cables to ensure low resistance to the rectifiers, return rails to have a sufficient cross section to lower the resistance of the return path. Transit Agency 6

S. No. 15 16 17 18 19 20 Transit Agency 5 Transit Agency 6 Transit Agency 7 Transit Agency 8 Transit Agency 9 Response from Transit Agencies Structure stray current drainage, Ungrounded negative return circuit, Yard TP isolation from main line, insulated rail fasteners, shop TP electric isolation from yard Electrically isolated yard, Insulated rail fasteners, Structure stray current drainage, Ungrounded negative return circuit, Diode grounded negative return circuit, Electrically bonded reinforced concrete structures Ungrounded negative return circuit – LRT only. Streetcar lines are grounded. Electrically bonded reinforced concrete structures Diode grounded negative return circuit, Insulated rail fasteners, Structure SC drainage (SC mat), Utility SC drainage, Electrically bonded reinforced concrete structures, Yard TP electrically isolated from mainline Ungrounded negative return circuit, insulated rail fasteners, electrically bonded reinforced concrete structures, isolated yard TP, utility SC drainage isolated from metro structure earth Yes, visual inspections are conducted Yes. Ongoing continuous rail replacement program Yes - Ongoing rehabilitation project replaces track rails, plates, clips, ties, and ballast that have exceeded the limits specified in maintenance standards. Yes - includes; track cleanliness, Ballast maintenance, and check on diode performance, bonding, and line insulation Visual inspections are carried out every other month Yes; continuous monitoring on two lines. The rest of the system will be included in coming years. No, unless a stray current problem is suspected or reported Yes every 3 to 4 years Yes, typically every few years (Footprint test). In the past substation monitoring several times each year A voltage limiting device connected between return rail and structure earth includes an voltage transmitter which is used to analyze if changes in the normal behavior is detected. This is performed on a monthly basis serudecorp deliated gnidulcni - seYoNoN A test plan is prepared when undertaking the Footprint test which includes running a single tram around the network whilst monitoring at traction substations and utility assets A written procedure is elaborated by the company in charge of the operation and maintenance of the metro. Confidential document oNoN The testing is only for track-to-earth resistance Not routinely but a measurement was included in a recent Footprint test Yes Not being measured The testing procedure breaks down the lines in sections Only limited data during construction – areas of embedded rail with less than the 5 ohm km are desired. unknown

S. No. 21 22 23 24 25 26 27 28 29 Transit Agency 5 Transit Agency 6 Transit Agency 7 Transit Agency 8 Transit Agency 9 Response from Transit Agencies seYoNseY No - generally corrosion is identified and therefore no detailed investigations are undertaken Yes Yes - Receive notification from the owner of the utility Yes; Arcing, pitting, flaking of metallic components Yes During embedded rail replacement corrosion of the rail was observed. No Engineering Department The engineering and the maintenance department Engineering and Track Maintenance Department Electrical Maintenance Department The O&M contractor has the obligation to maintain the system including stray current corrosion as well as corrosion due to other circumstances (environmental issues) Utilities will notify the agency if testing on their equipment indicates TP related SC problems Yes, however, things are under control Yes, and they have reported problems that have not yet been addressed Yes, however, things are under control Things are under control April 2005 (report provided) Don’t know From the records, in 1974 there was an issue with public utilities and stray currents. Stray current interference has been measured and investigated since start of operations An issue regarding water in the tunnel that was not drained sufficiently was noticed during operation and mitigated Mentioned in report Rail pad replacements, additional rail insulators, additional cross bonding A procedure was set up then to install blocking diodes, which is still the standard today for surface feeding substations Where SC interference is high (i.e. failing criteria) investigations are undertaken, and the issue is rectified to reduce SC A program to improve the drainage slope at few locations along the tunnel was set up and mitigation was performed Repairs have been completed 30+ years Repairs are always ongoing N/A metsyS weNelbaliava ylidaer toN elbaliava toNoNoN seYoNoNoNoN

S. No. 30 31 32 33 34 35 36 37 38 Transit Agency 5 Transit Agency 6 Transit Agency 7 Transit Agency 8 Response from Transit Agencies oNoNoNoNoN oNsnoitacol deifitnedi oNseYseYoN oNoN Stray current issues have modified the track maintenance plan to include for better isolation of negative rail. Stray current management is documented in the Engineering Reports for the transit agency No Not yet, repair work to occur next year(s) A/NA/Notni dekool yltnerruC - seYoN A/NA/N .stsoc tuo kaerb tonnaCwonk t’noDk57$ Less than 1 Don’t know On average 5-6 per year. Embedded rail was replaced No change Increased It has increased recently due to the age of the original equipment reaching the end of their lifecycle. Detailed historical data is not readily available to allow frequency of interference issues to be determined N/A N/A 7.3 miles of LRT 15 miles of double track HRT HRT miles 8.6 km, Streetcar miles 19.1 km 15 km of double track LRT Structure stray current drainage, Ungrounded negative return circuit, electrically bonded reinforced concrete structures, rail isolation, utility relocation and protection Ungrounded negative return circuit, Electrically bonded reinforced concrete structures, Structure stray current drainage, Utility stray current drainage, Cross bonding Isolating pads under rails and fasteners, rail on top of concrete slab or ties Utility stray current drainage Ungrounded negative return circuit, electrically bonded reinforced concrete structures Ungrounded negative return circuit, electrically bonded reinforced concrete structures Transit Agency 9

S. No. 39 40 41 42 43 44 45 46 47 Transit Agency 5 Transit Agency 6 Transit Agency 7 Transit Agency 8 Transit Agency 9 Response from Transit Agencies Total budget for operation, maintenance-of-way, and vehicle maintenance is $50 million $540 Million 2011 Operating budget - approx. $1.6 billion. Confidential Information Confidential Information MOW budget is roughly $15 million Not available Confidential Information Confidential Information $25k budget amount for rail isolation Don’t know Don’t know Don’t know Don’t know $600,000 (recent). This does not include Track Maintenance work. No cost Confidential Information $25k budget amount for rail isolation 5 X 600,000 = ~ $3.0 million No cost A/N%4 ~detcepxe eef tnatlusnoc oN oN14 ot esnopser eeSoN14 ot esnopser eeS .seYseYsrewsna evoba ees ,seY The stray current collector cable on a section has been stolen and is awaiting replacement. No All parties involved need to be educated on the requirements and importance of SC control and proper mitigation installation. Design criteria and technical specifications must include corrosion control None The hollow rail boots used for sound and vibration purposes are not good for electrolysis mitigation. Water gets trapped between the boot and the rail, the hollow boots are full of water, and the breaks in the boots have all contributed to much faster electrolysis corrosion of the rails at the breaks in the boots. It is recognized that the insulation of embedded rail in shared ROW is a challenge. Tests during construction should be undertaken to assist in finding any faults at an early stage. Include a surveillance system that informs of changes compared to normal conditions (surveillance of the voltage between return rail and structural earth) enoNenoN All utilities need to have an understanding of the issue and have personnel who can deal with it.

S. No. 48 49 50 51 Transit Agency 5 Transit Agency 7 Transit Agency 8 Transit Agency 9 Response from Transit Agencies No No oN Yes - there is a society for controlling Electrolysis that includes utility companies to discuss the electrolysis issues. Yes None available Yes, we meet once per year and are in contact with the representatives as issues and projects arise. Yes NACE specifications have been the most helpful. Ongoing design methodology influenced by lessons learned, filed measurements, collaboration with utility personnel. None The Consultants have used NACE and IEEE Std. 81, and the agency has its own design standards. Office of the Rail Regulator Tramway Technical Guidance Note No. 3 – Stray Current Design The VDV recommendations and the EN standards. The laboratory for Corrosion Protection and Electrotechnology .tsixe senilediug laredeF oNoNoN Guidance taken from EN 50122-2 No negative impact but the state railway has some requirements for other transportation system operations in the vicinity of their systems that are a challenge to fulfill. Transit Agency 6