Software Option for Plus versions

Rail Track Analysis

With a large percentage of track on modern railways consisting of continuously welded rails there is a requirement for accurate modelling of the interaction of the track with respect to any supporting bridge structures, and in particular, to calculate stresses and forces induced in the track by both thermal and train loading. 

The LUSAS Rail Track Analysis option permits track/bridge interaction analysis to the International Union of Railways Code UIC 774-3. It allows you to automatically build models from data defined in MS Excel spreadsheets, run an analysis, and quickly produce results in spreadsheet or LUSAS results file formats.

LUSAS Rail Track Analysis automatically updates the material properties associated with the track/structure interface based upon the position of the train or trains crossing the bridge


Model building

Track and bridge interaction models are built automatically in LUSAS in 3D from geometric, material property, and loading data defined in a MS Excel spreadsheet. Both thermal loading to the track and train loading due to acceleration and braking forces can defined. In accordance with the UIC774-3 code of practice, a user-specified element length is used to define the longitudinal embankment and bridge features. Rail clips, ballast movement, bearings and pier stiffnesses are all included in the analysis model. The model building dialogs allow for either one train crossing one or more structures, or for multiple trains crossing the same structure.

Spreadsheet data to build model

Spreadsheet input data
Full model built by LUSAS

Complete embankment and viaduct model built by LUSAS

Enlarged view of first span

Enlarged view of first span

Exploded isometric view showing embankment support and first span

Exploded isometric view of part of the model showing embankment support and the beginning of the first span

Analysis and results

When running an analysis, deck temperature loading can be considered in isolation for subsequent analysis of multiple rail configurations, or a full analysis can be carried out considering the combined temperature in the deck and rail loading. Because the response of the ballast and/or clips is nonlinear a nonlinear analysis always needs to be carried out. Results can be produced in either Excel spreadsheet or standard LUSAS results file format. User-defined load combinations can be specified. Spreadsheet results include axial forces in the rails for deriving in-service stresses and forces and moments in the deck structure.


Typical axial force results plot from LUSAS showing force in rails from temperature loading to the deck

Interactive Modal Dynamics (IMDplus) option

LUSAS Bridge software


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Any modelling and analysis capabilities described on this page are dependent upon the LUSAS software product and version in use.

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