WANTED: NEW STANDARDS FOR AFO

Paper presented by the author, senior research engineer for the General Railway Signal Co., at the 1974 annual meeting of the AAR Telecommunications and Signalling Dept. It deals overall with the problems of audio-frequency track circuits: (1) track impedance in relation to frequency; (2) voltage drop at the end of the circuit, in relation to circuit length and different frequencies; (3) effect of ballast resistance and safety margins for system operating depending on variations in ballast resistance; (4) preshunt and extended shunt phenomena; and (5) choice of the feed and receive end impedances of transmitters and receivers and of the figurative impedance of shunting by a vehicle. The author comments on the diagrams illustrating these phenomenae and draws conclusions as to the beneficial or harmful effects resulting from modifications of: (1) the impedance of the equipment used; (2) the frequency used; and (3) the energy level of the signal transmitted or the receiver gain.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/9675046
• Supplemental Notes:
  • This publication, Rail Engineering International, 13 also available from Broadfields (Technical Publishers) Limited Little Leights, Chelmsford, Essex CM3 1PF, England.
• Corporate Authors:

  Broadfields (Technical Publishers) Limited

  Little Leighs
  Chelmsford, Essex CMB 1PM,   England 
• Authors:
  • Freilinghaus, K
• Publication Date: 1974-5

Media Info

• Features: Figures;
• Pagination: p. 182-188
• Serial:
  • Rail Engineering International
  • Volume: 4
  • Issue Number: 4
  • Publisher: De Rooi Publications
  • ISSN: 0141-4615

Subject/Index Terms

• TRT Terms: Grade crossing protection systems; Track circuits
• Old TRIS Terms: Audio frequency track circuits; Grade crossing protection; Non-insulated track circuits
• Subject Areas: Operations and Traffic Management; Railroads;

Filing Info

• Accession Number: 00081262
• Record Type: Publication
• Source Agency: International Railway Documentation, Selection of
• Files: TRIS
• Created Date: Feb 27 1976 12:00AM