METRORAIL MIXES DIFFERENT TRANSIT TRACK TYPES

Miami's Metrorail, which opens the first 12 miles of its 21 mile system this year, is built primarily on elevated structures with ballastless track but has two short stretches of at-grade line with ballast and concrete cross ties. On the elevated beams, rails are secured by direct fixation fasteners and are supported by continuous reinforced concrete tie pads. The girders are designed to provide differential expansion as compared with the continuous welded rail on them. Configuration, track alignments and profiles generally conform with criteria established by other recent U.S. transit systems. The use of a tight track gauge is discussed; gauge widening is used on all curves to reduce high-side rail wear and avoid wheel sliding. Other features of curved track design are also described. Miami track is constructed to track twist limits as measured by a track geometry vehicle. Turnouts in ballastless track sections are supported on timber ties encased in rubber and set in concrete. The special design and construction are to maintain structural support, continuity and assure riding comfort.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/1763403
• Corporate Authors:

  Simmons-Boardman Publishing Corporation

  508 Birch Street
  Bristol, CT  United States  06010
• Authors:
  • Jackson, B
• Publication Date: 1983-8

Media Info

• Features: Photos;
• Pagination: p. 36-38
• Serial:
  • Railway Track and Structures
  • Volume: 79
  • Issue Number: 8
  • Publisher: Simmons-Boardman Publishing Corporation
  • ISSN: 0033-9016

Subject/Index Terms

• TRT Terms: Alignment; Ballastless track; Concrete slab track; Elevated structures; Gage (Rails); Railroad tracks; Railroad turnouts; Rapid transit; Specifications
• Geographic Terms: Miami (Florida)
• Old TRIS Terms: Gauge widening; Track alignment; Track structures
• Subject Areas: Construction; Public Transportation; Railroads;

Filing Info

• Accession Number: 00377824
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 30 1983 12:00AM