A sensor is described that measures the gage in a plane five-eighths of an inch below the top of the rail heads (as per the DOT/FRA track standards). The sensor can be mounted and can function on a railroad truck with no part of the sensor lower than three inches above the top of the rail heads. This eliminates the possibility of sensor damage due to interference with various track structures. A breadboard of the electro-optical gage sensor was constructed to demonstrate the feasibility of the concept. The light source was an RCA infrared (GaAs) injection-laser array. The total emitting region of this array was 150 X 0.08 mils, consisting of 12 individual diode emitting regions each 9 X 0.08 mils. This array essentially formed a line source which could be simply projected to form an appropriate slit-shaped beam of light. The detector system was a Reticon LC 600 line scan camera with a 256-element, linear photo-diode array. The camera had self-contained electronics for periodic scanning of the array to determine which diode(s) were illuminated above a predetermined threshold. Breadboard results were positive.

Media Info

  • Features: References;
  • Pagination: p. 528-529

Subject/Index Terms

Filing Info

  • Accession Number: 00156222
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Jul 19 1977 12:00AM