UC:IS:Track Geometry

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Note.png This page is mirrored from page UC:IS:Track Geometry in The railML® 3 wiki.
Track Geometry
Subschema: Infrastructure
Reported by: ÖBB
Stift.png (version(s) not yet specified)
For general information on use cases see UC:Use cases

Use case / Anwendungsfall

Track geometry; Gleisgeometrie

Description / Beschreibung

Modern track-laying and track maintenance is accomplished to a big extent with industrialised processes using sophisticated high-tech machines.

These machines are operated most economically when supplied with an accurate description of the track design layout. The observed deviations of the actual track geometry from design geometry are the major control parameters. Knowledge about points with uneven elasticity like bridges, tunnels, platforms, level crossings or switches/crossings is another important ingredient for efficient track works. Operational characteristics like design velocity or work type (new/reconstruction or maintenance) define the criteria for acceptance of work. A very complete list can be found in EN13231. Contract specific data supports the commercial sections of the processes.

The design layout consists of a "Horizontal Layout" and a "Vertical Layout". Positioning is required in higher accuracy levels than in most other railway applications. Combination of the horizontal layout and the vertical layout produces a space curve which shall enable a smooth movement of the trains. Transition bends are defined to prevent jolts. The European standard EN13803 provides a detailed description of the railway track alignment and its required parameters.

All of the above data is used by automatic guiding computers on the machines. Sensors on the machines produce a rich set of measurement data which can be used to document and verify the results of the work in very detailed manner.

Data Flows and Interfaces / Datenflüsse und Schnittstellen

The track geometry use case deals with two major data flows between two major components. They are marked blue in the following figure:


UCc TrackGeometry DataFlows 170407.png


The first component shall be called Track Geometry Repository as part of a Railway Infrastructure Data Base. It contains the RailTopoModel compliant railway network description enriched with the design layout and infrastructure description including also the essential information about points with uneven elasticity. Optionally, deviation information, operational characteristics and contract information may be provided. Most Track Geometry repositories are capable of receiving and processing measurement data in return to support acceptance of work and commercial settlement procedures.

The second component shall be called automatic guiding computer and it is located on the tamping machine. It processes the input data to direct and control all components of the machine during operations. An automatic guiding computer might also be able to collect sensor data to prepare a measurement data set for documentation of the work accomplished.

The first major dataflow originates from the Track Geometry Repository and supplies all available information to the automatic guiding computer.

The second major dataflow originates from the automatic guiding computer and provides feedback to the Track Geometry Repository.

Interference with other railML® schemas / Interferenz mit anderen railML®-Schemen


Characterizing Data / Charakterisierung der Daten

How often do the data change (update)?

The data support and secure a standardized process which takes place at each track laying construction site or track maintenance work area at least one time in both directions. At the ÖBB, for instance, there are more than 5000 occurrences (a generated measurement data file) per year.

How big are the data fragments to be exchanged (complexity)?

The data complexity depends on the configuration of the process and on the length of the work area. The element count ranges from the low hundreds up to several thousand data elements per occurrence.

Which views are represented by the data (focus)?

The data represent the following views:

  • Construction
  • Geometry
  • Measurement
  • Contract data
  • Operational characteristics of network

Which specific data do you expect to receive/send (elements)?

Core tamping data

  • Track Geometry (design layout + points of reference in sufficient accuracy and quantitiy)
    • 3D polyline describing 3D track layout:
      • Direction / course
      • gradient profile (height along the track)
      • superelevation of outer rail
      • relative height and height changes especially at switches
    • list of reference points with their geo-coordinates
  • precisely located points with uneven elasticity like bridges, tunnels, platforms, level crossings or switches/crossings enriched with metadata
    • Information about bridges
      • Type of ballast material: slab track vs. ballast
      • Precise position in relation to track
    • Information about platforms
      • Minimum and maximum distance between platform edge and track
      • State of the platform edge construction (damages?)
    • Information about level crossings
      • Type of ballast material: can be removed?
    • Information about distance between sleepers and sleeper material
    • Information about distance between neighbor tracks
    • Position of section insulators
    • Information about cables (communication, signaling, energy)
    • Meta data:
      • Origin of geometry data
      • Type of measurement procedure applied for collecting the data

Infrastructure object data ‘’(OPTIONAL)’’

  • E.g. sleepers

Supplementary information

  • loading gauge, track gauge, space between tracks
  • measurement data
  • contract data
    • contract number
    • name of contractor
    • name of purchaser
    • type of work: new or maintenance

operational characteristics

    • line classification
    • clearance gauge
    • (everything required by EN 13231)
  • Track design speed


  • geographic positions shall be given with micrometer precision for calculation purposes
  • the transfer of positions to the tamping machine is done in millimeter precision