The role of stiffness variation in switches and crossings

comparison of vehicle-track interaction models with field measurements

Ilaria Grossoni, Louis Le Pen, Pedro Jorge, Yann Bezin, Geoff Watson, Dimitrios Kostovasilis, William Powrie

Research output: Contribution to journalArticle

Abstract

The performance of Switches and Crossings (S&Cs) compared with plain line is complicated by the presence of movable parts, changing rail geometry and nonuniformities in the composite and/or trackbed stiffness. These features lead to complex vehicle-track interactions and higher maintenance costs. The trackbed stiffness is the least well controlled engineering property. A greater variability in trackbed stiffness leads to higher differential trackbed settlement and associated poorer track quality. At S&C changes in trackbed stiffness are exacerbated by changing rail properties which also contribute to changes in the overall composite track stiffness. This work focuses on the role of variations in stiffness on S&C performance. Field measurements of bearer displacement were carried out using geophones at an S&C equipped with Under Sleeper Pads (USPs). Vehicle-S&C interaction was modelled using a multi-body system and finite element method. The trackbed stiffness along the whole of the S&C was inferred using the measurements of track deflections in an iterative back-calculation taking account of changing rail properties. It is shown that not including the variation in trackbed/composite stiffness leads to significant under/overestimates of the wheel-railcontact forces. USPs are shown to reduce absolute maximum loads, but may increase the variation in deflection.
Original languageEnglish
Number of pages21
JournalProceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit
Publication statusAccepted/In press - 6 Oct 2019

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Switches
Stiffness
Rails
Composite materials
Seismographs
Wheels
Finite element method
Geometry
Costs

Cite this

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title = "The role of stiffness variation in switches and crossings: comparison of vehicle-track interaction models with field measurements",
abstract = "The performance of Switches and Crossings (S&Cs) compared with plain line is complicated by the presence of movable parts, changing rail geometry and nonuniformities in the composite and/or trackbed stiffness. These features lead to complex vehicle-track interactions and higher maintenance costs. The trackbed stiffness is the least well controlled engineering property. A greater variability in trackbed stiffness leads to higher differential trackbed settlement and associated poorer track quality. At S&C changes in trackbed stiffness are exacerbated by changing rail properties which also contribute to changes in the overall composite track stiffness. This work focuses on the role of variations in stiffness on S&C performance. Field measurements of bearer displacement were carried out using geophones at an S&C equipped with Under Sleeper Pads (USPs). Vehicle-S&C interaction was modelled using a multi-body system and finite element method. The trackbed stiffness along the whole of the S&C was inferred using the measurements of track deflections in an iterative back-calculation taking account of changing rail properties. It is shown that not including the variation in trackbed/composite stiffness leads to significant under/overestimates of the wheel-railcontact forces. USPs are shown to reduce absolute maximum loads, but may increase the variation in deflection.",
keywords = "S&C, Switch panel, Crossing panel, Trackbed stiffness, Composite track stiffness, Field measurements, Geophones, Vehicle-track interaction, FE approach, MBS approach, USP",
author = "Ilaria Grossoni and {Le Pen}, Louis and Pedro Jorge and Yann Bezin and Geoff Watson and Dimitrios Kostovasilis and William Powrie",
year = "2019",
month = "10",
day = "6",
language = "English",
journal = "Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit",
issn = "0954-4097",
publisher = "SAGE Publications Ltd",

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T1 - The role of stiffness variation in switches and crossings

T2 - comparison of vehicle-track interaction models with field measurements

AU - Grossoni, Ilaria

AU - Le Pen, Louis

AU - Jorge, Pedro

AU - Bezin, Yann

AU - Watson, Geoff

AU - Kostovasilis, Dimitrios

AU - Powrie, William

PY - 2019/10/6

Y1 - 2019/10/6

N2 - The performance of Switches and Crossings (S&Cs) compared with plain line is complicated by the presence of movable parts, changing rail geometry and nonuniformities in the composite and/or trackbed stiffness. These features lead to complex vehicle-track interactions and higher maintenance costs. The trackbed stiffness is the least well controlled engineering property. A greater variability in trackbed stiffness leads to higher differential trackbed settlement and associated poorer track quality. At S&C changes in trackbed stiffness are exacerbated by changing rail properties which also contribute to changes in the overall composite track stiffness. This work focuses on the role of variations in stiffness on S&C performance. Field measurements of bearer displacement were carried out using geophones at an S&C equipped with Under Sleeper Pads (USPs). Vehicle-S&C interaction was modelled using a multi-body system and finite element method. The trackbed stiffness along the whole of the S&C was inferred using the measurements of track deflections in an iterative back-calculation taking account of changing rail properties. It is shown that not including the variation in trackbed/composite stiffness leads to significant under/overestimates of the wheel-railcontact forces. USPs are shown to reduce absolute maximum loads, but may increase the variation in deflection.

AB - The performance of Switches and Crossings (S&Cs) compared with plain line is complicated by the presence of movable parts, changing rail geometry and nonuniformities in the composite and/or trackbed stiffness. These features lead to complex vehicle-track interactions and higher maintenance costs. The trackbed stiffness is the least well controlled engineering property. A greater variability in trackbed stiffness leads to higher differential trackbed settlement and associated poorer track quality. At S&C changes in trackbed stiffness are exacerbated by changing rail properties which also contribute to changes in the overall composite track stiffness. This work focuses on the role of variations in stiffness on S&C performance. Field measurements of bearer displacement were carried out using geophones at an S&C equipped with Under Sleeper Pads (USPs). Vehicle-S&C interaction was modelled using a multi-body system and finite element method. The trackbed stiffness along the whole of the S&C was inferred using the measurements of track deflections in an iterative back-calculation taking account of changing rail properties. It is shown that not including the variation in trackbed/composite stiffness leads to significant under/overestimates of the wheel-railcontact forces. USPs are shown to reduce absolute maximum loads, but may increase the variation in deflection.

KW - S&C

KW - Switch panel

KW - Crossing panel

KW - Trackbed stiffness

KW - Composite track stiffness

KW - Field measurements

KW - Geophones

KW - Vehicle-track interaction

KW - FE approach

KW - MBS approach

KW - USP

M3 - Article

JO - Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

JF - Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit

SN - 0954-4097

ER -