CO:segmentTable

Introduction

This page is under construction since April 30th 2025. Task: Finalize wording. Sorry for temporary problems. See the discussion page to find a summary of the tasks and to coordinate the work on this page. Recognize that the content of this page may change quickly. railML® Coord Rollingstock (talk) 11:37, 27 May 2025 (CET)

🗒️ This is a draft.

The element <segmentTable> provides a flexible mechanism for description of segments of arbitrary curves y = f(x) in railML^®. In contrast to the <valueTable> not particular points of the curve are defined but segments of a function representing the curve. The function used for modelling these curves is a polynomial expression of various order. Thus each line within this table has to be used as a recipe to build up the polynomial.

The table consist of the informative details of name and unit of each coordinate within the related attributes of the element <segmentTable>. The <polynomialHeader> takes the exponent values needed for the polynomial. The corresponding values in the @exponentValue represent the coefficients to be multiplied with. For a particular x-value the resulting P(x) can be calculated by this formula.

$P(x)=\sum _{i=0}^{n}a_{i}x^{i},\quad n\geq 0$

According the normal conventions 'x' means the independent variable. 'y' is direct dependent on 'x' and conforms to y = f(x). 'i' is the exponent used for the order of 'x', i.e. x^i.

The @segmentStartValue gives the lower limit of the interval the segment is valid for. The upper limit is the next higher @segmentStartValue or the maximum value given elsewhere.

🗒️ This article uses the unit label meter. As the reference for this Wiki is British English, the correct label is metre. Wherever the label meter occurs, it is meant equivalently to metre.

Documentation

Syntax

Autoexport from the XML-Schema for element CO:segmentTable of railML® version 3.3      UML-visualization of CO
Documentation	The representation of an x-y-curve as a list of segments described by polynomial coefficients
Subschema	common
Parents*	brakeEffort, decelerationTable, details, tractiveEffort
Children	polynomialHeader (1..*), segmentStartLine (1..*)
Attributes: functionValueName: This is the descriptive name for the y-coordinate resulting from the <segmentTable>. (obligatory; xs:string), functionValueUnit: This is the unit used for the values of the y-coordinate resulting from the <segmentTable>. For scalars the value '1' shall be given. (obligatory; xs:string; patterns: other:w{2,}; consider Use of tOtherEnumerationValue too.) Possible values: 1: means 'no unit of measure', is used for coefficients in the calculations of segment table of a rolling stock A: Ampere Hz: hertz km/h kWh m/s m/s/s: meters per second per second N: newton V: volt VA: Volt-ampere Vs: volt second W: watt, segmentStartValueName: This is the descriptive name for the x-coordinate in the <segmentTable>. (obligatory; xs:string), segmentStartValueUnit: This is the unit used for the values of the x-coordinate in the <segmentTable>. For scalars the value '1' shall be given. (obligatory; xs:string; patterns: other:w{2,}; consider Use of tOtherEnumerationValue too.) Possible values: 1: means 'no unit of measure', is used for coefficients in the calculations of segment table of a rolling stock A: Ampere Hz: hertz km/h kWh m/s m/s/s: meters per second per second N: newton V: volt VA: Volt-ampere Vs: volt second W: watt, zParameterName: This is the descriptive name of any parameter used in z-axis. (optional; xs:string), zParameterUnit: This is the unit used for the values of the z-parameter in the <segmentTable>. For scalars the value '1' shall be given. (optional; xs:string; patterns: other:w{2,}; consider Use of tOtherEnumerationValue too.) Possible values: 1: means 'no unit of measure', is used for coefficients in the calculations of segment table of a rolling stock A: Ampere Hz: hertz km/h kWh m/s m/s/s: meters per second per second N: newton V: volt VA: Volt-ampere Vs: volt second W: watt
*Notice: Elements may have different parent elements. As a consequence they may be used in different contexts. Please, consider this as well as a user of this Wiki as when developing this documentation further. Aspects that are only relevant with respect to one of several parents should be explained exclusively in the documentation of the respective parent element.

This element does not appear in railML^® 3.2 within the CO subschema. It is available only in railML^® 3.3. Do not hesitate to contact railML.org e.V. for further questions.

This element does not appear in railML^® 3.1 within the CO subschema. It is available only in railML^® 3.3. Do not hesitate to contact railML.org e.V. for further questions.

Changes 3.2→3.3

There exists an overview of all changes between railML^® 3.2 and railML^® 3.3 on page Dev:Changes/3.3.
Introduced with version 3.3.