1. Home
  2. TRID
  3. View Record
https://www.nationalacademies.org/trb/events

EMPLOYMENT OF NEW TECHNOLOGY INTO EXISTING TRANSIT SYSTEMS

The advent of microprocessor based vital interlocking equipment, microprocessor based non-vital communications and logic processing, microprocessor based track circuits, and microprocessor based carbone equipment has permitted the development of essentially standard hardware platforms that are highly customizable to the individual differences and nuances of existing transit properties. In San Francisco at the Bay Area Rapid Transit (BART) system, General Railway Signal Corp. (SASIB RAILWAY GRS) has incorporated its standard Vital Processor Interlocking (VPI) equipment and its standard Audio Frequency and Power Frequency Track Circuit equipment into an existing transit system, whose designs were established in the 1960's. Many of these designs were relatively unique to the transit industry at that time and remain so today. By creating only a few special interface boards for the standard hardware platforms, SASIB RAILWAY GRS was able to achieve full physical interface into the existing plant at tie-in locations (new locations utilized standard hardware only), SASIB RAILWAY GRS was able to create all of the features of the existing train control methodology plus new enhancements through vital and non-vital software accounted for the implementation of BART's cab signal, train-wayside communications (existing format plus a new modified format). ATP and ATO control algorithms, and communications to the Central Control Office. Train detection was implemented via either the standard Dual Code Audio Frequency track circuit or single rail Power Frequency track circuits with BART's 6-bit Frequency Shift Key cab signal overlayed in place of the standard rate coded cab signal. In a similar manner, SASIB RAILWAY GRS integrated its standard MICROCABMATIC on-board train control equipment into existing transit systems whose standards were established in the 1970's and earlier. Minimal hardware modifications were required to replace the existing on-board train control system originally supplied for Washington Metropolitan Area Transit Authority (WMATA) and Metropolitan Atlanta Rapid transit Authority (MARTA). The functionality originally provided by discrete logic and analog circuitry was duplicated and enhanced using a common hardware platform programmed to meet the individual functional requirements of each of these systems. The ATO function of the WMATA system originally required an entire rack of equipment was replaced by a single card file with hand full of printed circuit boards. Communications between the control console and the operators console that required nearly 100 discrete wires to each cab were replaced by a single serial communications link. The first generation MARTA ATC equipment that required five electronics modules was replaced by two programmable card files which duplicated the functionality of the original equipment while meeting the safety and operational standards established for the original equipment.

Language

  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 48-57

Subject/Index Terms

Filing Info

  • Accession Number: 00750122
  • Record Type: Publication
  • Report/Paper Numbers: Volume 4
  • Files: TRIS
  • Created Date: Jun 12 1998 12:00AM