Modeling Ballasted Tracks for Pollutants

Details

• Creators:
  Molinas, Albert ; Mommandi, Amanullah
• Corporate Creators:
  Hydrau-Tech, Inc.
• Corporate Contributors:
  Colorado. Dept. of Transportation. Research Branch ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Rail transit
  • Light rail transit
  • Drainage
  • Runoff
  • Hydrology
  • Pollution control
  • Pollution
  • Heavy metals
  • Permits
  • Best practices
  More +
• Publication/ Report Number:
  CDOT-2012-7
• Resource Type:
  Tech Report
• Geographical Coverage:
  Colorado
• Edition:
  Final.
• Corporate Publisher:
  Colorado. DTD Applied Research and Innovation Branch
• Abstract:
  In this study, the Regional Transportation District’s (RTD’s) light rail operations were examined for pollutant production and runoff. To ; accomplish this, a laboratory study utilizing a rainfall-runoff facility was conducted. Input to this laboratory model was provided by ; using RTD’s design criteria, data from existing installations, and a field study to sample surface materials along ballasted tracks. A ; rainfall-runoff physical model of the light rail system was constructed at the Colorado State University Hydraulics Laboratory to study ; the effectiveness of the as-built ballasted tracks in the railroad environment. This model was subjected to Denver hydrology and ; environmental conditions using the available local rainfall information and pollution data. A 1-to-1 model of an 8-foot railroad segment ; was constructed using RTD’s design criteria and materials. A rainfall simulator was designed to vary rainfall duration and intensity. The ; model had the capability of capturing all of the runoff for volumetric measurement of the quantity and quality of the runoff. ; Potential sources of pollutants from a light rail system are: i) metal introduced from track abrasion; ii) metal from wheel abrasion; iii) ; material from disk brakes; and iv) material from overhead power lines, etc. These quantities were computed using RTD’s maintenance ; records for wheel truing, brake rotor maintenance, track replacement, copper power line replacement, and field sampling of light rail ; tracks. For field measurements, toe regions of tracks near the most heavily travelled sections of the light-rail system were sampled at ; RTD’s Broadway Light Rail Station. The measured iron and aluminum concentrations from the field samples were introduced into the ; laboratory ballasted-track model and were subjected to various rainfall events. Runoff water and soil samples collected during and after ; different frequency events were analyzed to trace the effectiveness of ballasted tracks for capturing pollutants. ; Conclusions from the study: ;  Water leaving ballasted tracks carries only a small fraction of the heavy metals that are introduced into tracks from the light rail ; operations. ;  Heavy metal concentrations at the most heavily travelled light rail station showed that pollutant concentrations were far below ; the regulatory limits. ; Implementation: ; It is recommended that the CDOT use the findings of the study in the CDOT Drainage Design Manual.
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• Format:
  PDF
• Funding:
  107.00
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/24781/dot_24781_DS1.pdf
• File Type:
  [PDF - 3.39 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:81c791c02e31d186fb3944cffd56efadaeee2073968c4dc71346b7f9ea1b8522