HIGH-SPEED TRAINS PROMPT SEARCH FOR NEW COMMUNICATIONS MEDIA

THE OFFICE OF HIGH SPEED GROUND TRANSPORTATION IS EXAMINING VARIOUS TECHNIQUES FOR COMMUNICATIONS TO AND FROM THE MOVING VEHICLE. COMMUNICATIONS LINKS BETWEEN THE TRAIN AND WAYSIDE ARE A HELP TO PASSENGERS BUT ARE EQUALLY USEFUL FOR CONTROLLING THE TRAIN, INDICATING ITS POSITION, COMMUNICATING WITH THE CREW, OR WARNING OF OBSTACLES ON THE TRACK. THERE ARE MARKED DIFFERENCES BETWEEN EQUIPMENT IN USE AND THAT PLANNED FOR TRAINS WITH SPEEDS OF 250 MPH AND BEYOND. AT PRESENT, THE METROLINER USES 6 2-WAY RADIO CHANNELS ASSIGNED BY THE FEDERAL COMMUNICATIONS COMMISSION AND EMPLOYS FREQUENCY PATTERNS TO OBTAIN 11 VOICE CHANNELS. WHEN TRAIN SPEEDS RISE TO 250 MPH, IN PLACE OF FM CARRIERS, THE USE MAY BE OF EITHER SURFACE-WAVE TRANSMISSION LINES OR WAVE GUIDES RUNNING PARALLEL WITH THE TRACK TO COMMUNICATE TO AND FROM THE MOVING TRAIN. RESEARCH EFFORTS INCLUDE ELECTRIC AND ELECTROMAGNETIC FIELD PATTERNS FOR THE SURFACE-WAVE TRANSMISSION LINE, SOLID DIELECTRIC SURFACE WAVE GUIDE, W-SPEED SURFACE WAVE GUIDE, LEAKY WAVE GUIDE, AND LEAKY SLOT WAVE GUIDE. THE COST EFFECTIVENESS OF THE VARIOUS DESIGNS WILL BE STUDIED TO SEE WHICH WARRANTS FURTHER DEVELOPMENT. THE FOLLOWING FACTORS WILL ENTER INTO THE SELECTION: (1) DISPERSION OR DISTORTION DUE TO ECHO EFFECTS AND HOW THE COUPLING OF HIGH-SPEED ANTENNA AFFECTS TRANSMISSION CHARACTERISTICS, (2) ATTENUATION LOSSES IN THE GUIDE, (3) RELIABILITY AND INCORPORATION OF FAIL-SAFE SUBSYSTEMS, (4) METHOD OF MODULATION AND THE APPLICABLE VARIATIONS, (5) MAINTAINABILITY, AND (6) COST VERSUS OPERATIONAL REQUIREMENTS.

• Supplemental Notes:
  • Vol 2, No 3, PP 24-25, 3 FIG
• Corporate Authors:

  Communications User

  ,    
• Publication Date: 1970-3

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Communication systems; Dielectric materials; Electromagnetic fields; Ground transportation; High speed ground transportation; High speed vehicles; Modulation; Railroad transportation; Speed; Transmissions; Waveguides
• Old TRIS Terms: Electric communication systems; Modulation
• Subject Areas: Highways; Operations and Traffic Management; Railroads;

Filing Info

• Accession Number: 00225789
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 26 1970 12:00AM