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Uploaded byRichard Bellew
NRM Ride Quality Assessment
Rick Bellew is the Vice President of Corporate Development for Nevada Railroad Materials. He has over 10 years of experience in various railroad positions. Nevada Railroad Materials is a railroad tie collection, rehabilitation, and sales company based in Ogden, Utah with plants in several states. They provide various track maintenance and inspection services including ride quality assessment using an accelerometer-based system called rMetrix to identify track issues. They offer additional consulting services such as internal track audits, state of good repair assessments, and capital tie maintenance programs.
NRM Ride Quality Assessment
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- 5. Ride Quality The capability of the railroad vehicle suspension to maintain the motion within the range of human comfort and or within the range necessary to ensure that there is no damage to the cargo it carries. Depends on ◦ Displacement, Acceleration, rate of change of acceleration and other factors like noise, dust, humidity, and temperature. Sperlings Ride Index – Older Version ◦Used by Indian Railways ◦ Ride Comfort – Vehicle being assessed according to the effect of the mechanical vibrations on the human body. ◦ Ride Quality – Vehicle itself is being assessed A is the peak acceleration in cm/s2, f is the frequency in Hz and F the frequency dependent weighting factors that expresses human vibration sensitivity. F is different for vertical and horizontal vibration components. ISO ◦ International Standards Organization ◦ Influence of vibration on the human body is expressed by the fatigue time. ◦ Three Levels of fatigue Time ◦ Decreased Proficiency, ◦ Exposure Limits, ◦ Reduced Comfort Boundary
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- 7. Comfort Guidelines – ISO 2631 Human reaction to vibration ◦ Function of amplitude and frequency of acceleration applied to the body. ◦The direction (Horizontal and Vertical) and character of the motion (Linear or rotation). Frequency range of 1-80 Hz as set by ISO Limits cover human sensitivity to vertical and lateral vibration to periodic vibration exposure time ranging from 1 minute to 24 hours. Uses 1/3 octave bands at 10 Hz
- 8. What is rMetrix Fra inspectors are using the system in each region. ( I used an early version). Ride Quality System ◦ Runs off laptop ◦ Uses Accelerometer –Tri-axial accelerometer ◦ MEMS Accelerometer – Analog device with an iSensor. Measures acceleration, tilt, shock, and vibration in performance drive applications. ◦ Uses a Free Scale Chip inside which allows communication with laptop. ◦ USB Micro Controller ◦ Temperature Compensation ◦ Calibrated annually ◦ GPS location provided by device and GIS mapping data provided by the FRA.
- 9. rMetrix Real time, geo-spatially correlated ride quality data Software ◦ Compares the longitudinal, lateral, and vertical acceleration signal strength against a pre-defined safety threshold to detect abnormal conditions (exceptions) – 49 CFR Part 213.333. Excessive Vertical Acceleration ◦Profile or cross level geometry deviations Excessive Lateral Acceleration ◦ Alinement or gage deviations Abnormal vibration data could point to problems with worn wheels or the primary or secondary suspension components such as springs or dampers.
- 10. Values 49 CFR Part 213.333 ◦ Carbody Lateral Peak to Peak – Highest point of deviation to lowest point within 1000 mls, or 1 second. ◦.500 g force ◦ Carbody Vertical Peak to Peak – Highest point of deviation to lowest point within 1000 mls, or 1 second. ◦ .600 g force If the inspection returns no results, we can tighten the thresholds. If the inspection returns more than anticipated, we can loosen the thresholds.
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- 13. Additional Services Third-Party compliance internal audit of your contracted maintenance of way contractor. ◦ This service includes: ◦ A review of at least one-months track inspection records. ◦Rail flaw defect repair review. 213.113 ◦ Rail joint inspection and welding compliance. 213.121 ◦ Continuous welded rail plan contents and field compliance. 213.119 ◦ Track Inspection compliance. 213.233 ◦ Switch inspection compliance. 213.235 ◦ Inspection of rail (Internal) compliance. 213.237 ◦ Designation of inspectors compliance. 213.7 a, b, c and d ◦ On-Track Safety compliance. 214 ◦ Roadway Maintenance Machine Compliance 214 NRM provided inspector to conduct a full Part 213 inspection of the entire track structure. (An internal inspection BEFORE the FRA inspection) ◦ This could take a week, or four weeks depending on multiple variables which should be discussed prior to scheduling the inspection. State of Good Repair Assessment ◦ NRM can provide an inspector who will conduct a full or sample SOGR assessment. SOGR assessments are ideal when an agency wants to keep track of the condition of the track structure prior to, during, and after the term of a contract has ended or is ending in the near future. This allows the agency to make a determination as to the condition of the track before, and after the term of the contract. NRM can also make recommendations after the inspection in order to help make decisions to extend the life of the physical plant. Ratings are typically between 1 and 5, and color coded. A baseline inspection should be performed, and periodic inspections to assess if the condition has improved, or degraded. Capital Tie Maintenance Program ◦ NRM utilizes state of the art systems which allow our inspectors to grade each and every railroad tie between MP locations. The condition is logged into a ruggedized palm top pilot. The inspection data is uploaded into a software program provided by Zeta-Tech. From this software system, NRM is able to make a recommendation on tie replacement using a number of variables such as: ◦ Replace every 2, 3, 4, 5 tie clusters ◦ Build a capital tie replacement program to bring class up to a higher class for speed increases. ◦ Build a capital tie replacement program for minor maintenance.
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