Rail: Interlocking

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Interlocking

Primary Guidance

  • Select universal crossover over double crossover if there are no site constraints
  • All special trackwork should be on a horizontal and vertical tangent whenever possible
  • Standard Details should be used in order to minimize the spare parts inventory, simplify maintenance, and eliminate manufacturing costs associated with specially made components

Discussion

  • Where an interlocking requires a pair of crossovers, the crossovers should be set in universal crossover configuration for better operations and maintenance. If site constraints preclude universal crossover configuration, a double crossover should be used.
  • All special trackwork should be on a horizontal and vertical tangent whenever possible to minimize customization manufacturing and installation costs. Replacing an existing interlocking within a curve should consider if realigning the tracks would be more cost effective than manufacturing the special trackwork.
  • MTAMaryland Transit Authority Standard Details should be used for all interlocking special trackwork, including turnouts, single crossovers, double crossovers, and all associated components, in order to minimize the spare parts inventory, simplify maintenance, and eliminate manufacturing costs associated with specially made components.
  • The distances between switch points of closely spaced turnouts in ladder tracks, universal crossovers, and other special trackwork layouts should allow for the use of standard special trackwork components without modifications. Designers should carefully consider train routings through closely spaced special trackwork and avoid track geometrics that are likely to exceed the capabilities of the vehicle, result in excessive wear, or result in a poor ride quality.
  • For MARCMaryland Area Regional Commuter Service , special trackwork design should conform to the latest requirements of the Operating Railroad, which owns the track (e.g. Amtrak or CSX). Special trackwork design on portions of track owned by MTAMaryland Transit Authority should conform to the latest requirements of the Operating Railroad to which the MTAMaryland Transit Authority portion connects.

See Also