Post on 19-Feb-2016
description
Turnouts - 1© Transportation Technology Center, Inc., a subsidiary of the Association of American Railroads, 2015
Section 4 - Turnout Modeling
®®TransportationTechnology Center, Inc
© TTCI/AAR, 2015, Turnouts p2®
Turnout Nomenclature
© TTCI/AAR, 2015, Turnouts p3®
Switch Geometry
© TTCI/AAR, 2015, Turnouts p4®
Rail Profile Variations & W/R Contact
© TTCI/AAR, 2015, Turnouts p5®
Turnout Modeling Methodology in NUCARS® Traditional W/R rigid contact model (WNT tables)
Unstable (chattering)when two-point contact occurs Can’t simulate rail roll movement
Penetration W/R contact model (Fit files) Instable (spikes)when rail profile shape changes
Double rail model (Fit files) Stable results Involve primary and secondary rail trajectories and
profile variations Has been used for various special track work
(foundation, frog, crossing etc.) modeling
© TTCI/AAR, 2015, Turnouts p6®
Turnout Modeling - Rigid W/R Contact Model
Traditional rigid W/R Contact Model In .run file, use key word: \W/R Contact Master
Geometry File 'AREMA20.WRM’ includes a series of WNT files See Chapter 11.5 for details of making a WRM file
Can’t use Track Model Can only use spring and damper connections
underneath rail Need to calculate guard rail geometry Guard rail rigidly attached to stock rail See Chapter 11.6 for details of making WNT file for
flange back contact with guard rail
© TTCI/AAR, 2015, Turnouts p7®
Turnout Modeling - Penetration Contact Model
W/R Penetration Model In .RUN file, use key word: \Rail Geometry Master
File 'AREMA20.RLM’ includes a series of FIT files See Chapter 11.5 of for details of making RLM file
Can use Track Model or use spring and damper connections underneath rail
Guard rail is defined in Fit file (flangeway clearance, guard rail height, stiffness, damping etc.)
Guard rail can move relative to stock rail
© TTCI/AAR, 2015, Turnouts p8®
Typical Measured Switch Rail Profiles
Measured every foot