2015 Rail Safety Seminar & Expo: April 20-22, Bus Safety Seminar & Expo: April 22-23, 2015

Transcription

1 2015 Rail Safety Seminar & Expo: April 20-22, Bus Safety Seminar & Expo: April 22-23, 2015 PRESENTER BIO: Kyle Jordan Senior Software Engineer, L.B. Foster Kyle Jordan has 14 years of experience with the design and development of remote site monitoring systems. He joined L.B. Foster Salient Systems in 2011 as a Software Engineer on the Rail Stress Monitor System. During this time, he has held several roles including Lead Software Engineer for the Rail Stress Monitor System and Project Manager for several key Engineering projects. Prior to joining L.B. Foster, Kyle lead multiple Engineering projects for Kentrox, Inc., where he co-authored a patent titled "Management system for monitoring and controlling remote sites and equipment". Kyle completed his B.S. in Electrical and Computer Engineering from The Ohio State University in 2000and a M.S. in Computer Science from Franklin University in POWERPOINT PRESENTATION IS INCLUDED ON THE FOLLOWING PAGES OF THIS DOCUMENT

2 Rail Neutral Temperature Measurement Technology and Global Case Studies Kyle Jordan Senior Software Engineer L.B. Foster Salient Systems Co-presenters: Kevin Oldknow, PhD, Walt Spicker

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4 Overview Rail Neutral Temperature introduction Related safety issues RNT measurement technology RNT measurement and implementation case studies

5 Case Studies Chicago, IL Japan South Africa

6 RNT Fundamentals Temperature at which there is no compressive or tensile longitudinal forces in rail RNT: Rail Neutral Temperature SFT: Stress Free Temperature Tn: Neutral Temperature CWR: Continuously Welded Rail

7 Development of Forces in CWR With temperature increase/decrease, the rail wants to expand/contract; but it can t because it s constrained, so instead it develops longitudinal forces (referred to as forces due to constrained thermal expansion ) COMPRESSION TENSION Elongation but NO stress Stress but NO elongation

8 Potential Longitudinal Stress Issues High compressive forces Rail Buckle High tensile forces Rail Break Proper RNT management is critical for safe rail operation!

9 Traditional RNT Risk Mitigation Methods Target RNT upon rail installation/track-work Hot weather speed restrictions Periodically check RNT with one-time measurement technology Hot and cold weather track inspections

10 RNT Monitoring System Overview RailStress Module Welded foil strain gauge for strain and temperature measurement Wireless communication with wayside collection device Designed for 10 year battery life

11 RNT Monitoring System Overview Wayside Reader Device Wireless communication with modules Stores and forwards to data server Network connection via cellular, WiFi or Ethernet

12 RNT Monitoring System IntelliTrack Navigator Graphing capability Satellite/map view of equipment locations Ability to configure alarm definitions Detection and notification of alarm events

13 Graph Overview RNT Temperature Stress

14 Stress Calculation TSTRESS = RNT TR TR: Temperature of rail TSTRESS: Stress temperature 0 degrees: No tension or compression TSTRESS >0 degrees: Tension TSTRESS <0 degrees: Compression Stress is in units of Fahrenheit/Celsius!

15 Stress Calculation P=EAα(RNT TR) P/A = σ = Eα(RNT TR) σ / Eα = TSTRESS P: Longitudinal force within rail E: Young s modulus rail steel A: Cross-sectional surface area of rail α: Coefficient of thermal expansion of rail steel σ: Normal stress TR: Temperature of rail

16 Stress Calculation Example US-115# Rail Force = # (RNT - Rail Temperature ) RNT Rail Temp Stress ( F) Force (lbs) (US-115# Rail) 100 F 100 F 0 F 0 lbs 100 F 32 F 68 F 149,600 lbs 75 F 120 F -45 F -99,000 lbs Stress = RNT - Rail Temperature

17 RNT Monitoring - CTA Location: Chicago, IL Traffic: Transit Install date: September 2013 Total of 10 sites, double track, 1 module per rail at each site Target RNT: 100 F Goals of system: Monitor RNT over time Analyze stresses near rigid structures

18 RNT Monitoring - CTA Street view of all 10 sites

19 RNT Monitoring - CTA Aerial view of single site

20 RNT Monitoring - CTA

21 RNT Monitoring - CTA

22 RNT Monitoring - CTA RNT is not constant! RNT of rail 1: 85 F RNT of rail 2: 71 F

23 RNT Monitoring - CTA Highest compressive stress Temp Max: 129 F Temp Min: -8 F Stress Max: 88 F Stress Min: -41 F

24 CTA Results Integration of monitoring system into CTA s processes is still in progress. No stresses have reached a concerning threshold RNT values have changed over time Assurance that RNT and stress is still within safe limits

25 RNT Monitoring South Africa Location: South Africa Traffic: Freight and some passenger Install date: June 2013 Target RNT of rail: 104 F Goals of system: Monitor RNT over time Set alarming points for RNT and buckle hazard Verify vandal-resistant nature of system

26 RNT Monitoring South Africa Specialized Wayside bracket Installed 15 feet above grade Raise and lower with specialized pole 1 module per rail at each site

27 RNT Monitoring South Africa

28 RNT Monitoring South Africa Buckle hazard alarm RNT Stress Average of left/right rail

29 Buckle Hazard Alarm Track Strength Know/Understand the Track s Buckling Strength: rudimentary knowledge of the CWR track s buckling strength and safety concepts is important. Key Parameters Track resistance lateral resistance Alignment defects/curvature Train loads/dynamics Rail neutral temperature Temp Increase Rule of Thumb To Cause Buckling Track Condition Strong Average Weak* Buckling Strength (Temperature increase above neutral, F) *Most CWR Policies conservatively assume that track s buckling strength is best approximated by weak track considerations (i.e. temperature increase of 60ºF above rail neutral temperature).

30 Buckle Hazard Alarm Buckle Margin of Safety Safety buffer to ensure alarm is generated before buckle condition occurs T T Bmax Alarm Level Buckle Margin of Safety (BMS) F T Bmin BMS Warning 25 RNT T all T R Buckle Amplitude Critical 20 T R = T all BMS min + RNT

31 Buckle Hazard Alarm How does it work? T R = T all BMS + RNT RSM Measures/Warns On Estimated Track Strength (Allowed Stress) 25 F Rail Neutral Temperature As long as : (T R RNT)< (T all BMS); track is OK Temperature increase has to be less than the track s buckling strength minus a margin of safety or conversely: (T R RNT) > (T all BMS); track is unsafe

32 Buckle Hazard Alarm - Revisited RNT Stress Buckle Margin of Safety Track Strength Weak (60 F / 33.3 C) Stress crossed Warning threshold

33 Buckle Hazard Alarm Result RNT of the rails at time of alarm Rail 1: 62 F / 17 C Rail 2: 60 F / 15 C Target RNT: 104 F / 40 C Highest compressive stress: -48 F / 26 C Result: Railway was notified of alarm and repair was scheduled

34 RNT Monitoring South Africa Correcting RNT: rail de-stressing Rail 1 RNT: 115 F / 46 C Rail 2 RNT: 100 F / 38 C Both rails cut

35 South Africa Results Several alarms have generated repair action Corrective action may have prevented a derailment Product selected as one of the two finalist systems for large-scale deployment Only welded strain gauge product approved for use in South Africa

36 Conclusion Safety issues related to longitudinal stress Continuous monitoring advantages: Provides vision into stress Rapid notification of events Verify RNT is within safe range

37 Questions?