Operational and design objectives are within reach using NUCARS® modeling software. Whether the goal is to reduce risk of derailment, increase passenger ride comfort, maximize component life, optimize designs, improve high wheel/rail wear rates, reduce rolling contact fatigue, improve poor wheel/rail performance, or any combination of the above, NUCARS® software can provide the data required by simulating the dynamic response of railroad vehicles to specified track conditions. NUCARS® software provides online calculation of wheel/rail contact using Kalker’s non-linear theory. It can be utilized to include multiple overlapping contact point, nearly any combination of worn wheel and rail profiles, including guard rails and back-of-flange contact, as well as changing rail profiles along the track section being modeled. The software provides for optional multi-body representation of track structure including rails, fasteners, sleepers, ballast, slabs and bridges, and it can simulate failed components and changes to the structures along the track. Gain knowledge and achieve objectives with NUCARS®. Available for license as well as consultation with TTCI experts.

Simulate Any Rail Vehicle
Freight, Passenger Coaches, Locomotive, Light Rail Vehicle, Metros and High-Speed Trains.

Simulate Any Types of Track
Tangent & Curves, Turnouts and special trackwork, Track irregularities, Measured Track Geometry, Track structure and Flexibilities.

Full Nonlinear Wheel-on-rail Contact Calculations
Multipoint contact, flange back contact, independently rotating wheels, variable W/R friction per wheel and along track.

Certification Support
NUCARS can be used to satisfy Federal Railroad Administration’s requirements under 49 CFR Appendix D to Part 213 – Minimally Compliant Analytical Track (MCAT). MCAT simulations are used for qualifying vehicles to operate at high speeds and at high cant deficiencies.

Faster Results
NUCARS® multi-body dynamics software is supported by robust real-world testing and peer reviewed reports. Analyze existing and new vehicle full-body models faster than finite element analysis.

A Tailored Experience
A flexible user interface allows users to visualize their models. MxV Rail’s experienced engineering team can work with you to develop unique solutions to your needs, as well as train staff to utilize the software’s full capabilities.



The NUCARS® software was benchmarked against a number of other railway vehicle dynamics computer programs during a cooperative benchmarking exercise sponsored by Manchester Metropolitan University in 1997 and 1998, [1]. This exercise demonstrated that NUCARS® compares favorably with other leading railway vehicle simulation programs, including VAMPIRE, GENSYS, ADAMS/Rail-MEDYNA, and SIMPACK. In general, NUCARS® simulation results were very similar to those of VAMPIRE and GENSYS. In terms of computational speed, NUCARS® and VAMPIRE were similar and considerably faster than the other programs.

The Beta track model capabilities of NUCARS® have been benchmarked against a number of other Track Models during a cooperative benchmarking exercise sponsored by Rail-CRC of Australia. This benchmark was coordinated by Queensland University of Technology in Brisbane. The results of the benchmark were reported at the 2005 International Heavy Haul (IHHA) conference in Rio de Janeiro, Brazil, [2].

The core strength of NUCARS® software development is the continuous benchmarking of simulations with test measurements of wheel/rail interaction forces and vehicle dynamic response. [3,4,5,6,7] provide an overview of the a number of validation and comparison efforts. Members of the NUCARS® development team are active participants in research and development projects at TTCI’s Pueblo test facility and for MxV Rail’s customers worldwide in the passenger and freight railway industry.


  1. Iwnicki,S., Editor, “The Manchester Benchmarks For Rail Vehicle Simulation”, Supplement To Vehicle Systems Dynamics, Volume 31 (1999), Swets & Zeitlinger B.v., Lisse, The Netherlands, 1999
  2. Steffens, D., Murray, M., Establishing Meaningful Results From Models Of Railway Track Dynamic Behaviour, Proceedings Of The 8th International Heavy Haul Association (IHHA) Conference, Rio De Janeiro, Brazil, June, 2005
  3. Blader, F.b., Elkins, J.a., Klauser, P.e., Wilson, N.g., “Development And Validation Of A General Rail Vehicle Dynamics Simulation (Nucars),” Asme-Ieee Joint Railway Conference, Philadelphia Pa. April 1989.
  4. Elkins, J.a., “Experimental Validation Of Multi-Body Programs” ,
  5. Wilson, N.g., Gurule, S., “Application Of Instrumented Wheelset Technology To Transit System Research And Development”, Asme-Ieee Joint Railroad Conference, Boston, Ma, March 1997.
  6. Elkins, J.a., Brickle,B., Singh, S., Wilson, N.g., Wu,H.,”Track Stucture Modelling With Nucarstm And Its Validation”, Proceedings Of 17th IAVSD Symposium, Lyngby, Denmark. August 2001.
  7. Shu, X., Wilson, N., Sasaoka, C., Elkins, J., “Development Of A Real-Time Wheel/Rail Contact Model In Nucars™ And Application To Diamond Crossing And Turnout Design Simulations”, Presented At The 19th IAVSD Symposium, Milan, Italy, August 2005
  8. Kalker, J.j., ‘The Computation Of Three Dimensional Rolling Contact With Dry Friction,’ International Journal For Numerical Methods In Engineering, Vol. 14, Pp. 1293-1307, 1979.
  9. Wilson, N.g., Gurule, S.,”Simulation Of Wheel/Rail Interaction In Turnouts And Special Trackwork”, Proceedings Of 16th Iavsd Symposium, Pretoria, South Africa. September 1999.
  10. Li, D., Elkins, J.a., Otter, D.e., Wilson, N.g.,”Vehicle/Track Dynamic Models For Wheel/Rail Forces And Track Response”, Heavy Vehicle Systems, International Journal Of Vehicle Design, Vol. 6, Nos. 1-4, Pgs 345,359, 1999.
  11. Elkins, J.a., “Simulating High Speed Rail Using Nucars: A General Rail Vehicle Dynamics Program”
  12. Elkins, J.a., Klasuer, P.e., Blader, F.b., “Applications Using Nucars; A General Purpose Rail Vehicle Dynamics Simulation”

Installation Instructions

  • Connect your NUCARS® hardware key to your computer.
  • Download and extract the contents of the zip file.
  • Run the setup.exe
  • The program will determine if your license is valid.
  • If the license is valid, the install program will then install the full NUCARS® Installation.

Updating Your NUCARS® Key

  1. Send Update Request

If updating your key on a new computer, contact the NUCARS help desk for installation procedure. Go to step 2 if you have already sent your request and received your update file.

    • Launch the NUCARS® Control Panel
    • Select Tools > Request License Update to launch the SafeNet Secure Update Utility.
    • Click Generate License Code.
    • Create a file using the following naming format:
    • companyname_key#.req
    • (key# is the 5 digit number engraved on the back of the key below TTCI-NUCARS)
    • Email the file to: with the subject line: NUCARS Update Request.
    • Include your name, company name, phone number, and key # in the email.

Once we confirm that your license has been paid, we will send you an update code file near the end of the month. Follow the instructions below on how to use this to update your key.

2. Update Your Key

If you sent a request to update your key and we have received payment you will be receiving and update file to be used to extend your license to January 31, 2023. If you have multiple keys, make sure the correct update file is used, as this file is unique to the request file that was sent for each key.

    • To perform the license update:
    • Select Tools > Request License Update on the NUCARS Control Panel to launch the SafeNet Secure Update Utility.
    • In the dialog box, click on the folder to find the .upw you received by email.
    • Click the Activate Application button.
    • Exit.

Safenet Sentinel Key Driver

Many technical problems involving the Sentinel keys can be resolved simply by installing the latest system drivers. Please download and install the latest driver below.

This driver update is compatible with Windows 98/ME/NT/2000/XP/Server 2003/2008/Vista & Windows 7/8/10 (32 bit and 64 bit)

Download Safenet Secure Update and Sentinel Key Driver

Safenet Secure Update Utility 1.3.1 includes Sentinel System Driver Installer v7.6.1.


Installation Troubleshooting

If you are running LabVIEW 2009 or later and are unable to install the Sentinel Driver, make sure LogosXT is running and not the old Logos service.

Disabling the Old Logos Service

  • Create a Logos directory on your computer in the following location:
    • For Windows XP:
      • C:\Documents and Settings\All Users\Application Data\National Instruments\Logos
    • For Windows Vista & Win7:
      • C:\ProgramData\National Instruments\Logos
  • In that directory create a text file called
    • Logos.ini
      • Paste the following text in that file:
        • [logos]

If you have any questions regarding installation of these upgrades, security keys or use of NUCARS®, please contact the NUCARS Help Desk.

TEXTPAD® Text Editor Plug-in for NUCARS®

Most NUCARS® users know that frequent editing of text files is necessary to modify anything from system files to track files to input files. Some text editors can add extra control characters, or ghosts as we like to call them, and it can be very cumbersome to edit and change multiple files.

MxV Rail has been using a program called TextPad® by Helios Software Solutions for the last few years and it has turned out to be a very useful and powerful text editor. It allows you to edit many files at once, even performing find-replace operations across many files at the same time. It also uses syntax sheets so that keywords, comments, and text show up in different colors making large text files much easier to read.

Download TEXTPAD®

TEXTPAD® Installer


Download NUCARS® Syntax Sheet

NUCARS® Syntax Sheet


How to Activate the Syntax Highlights

If you are running LabVIEW 2009 or later and are unable to install the Sentinel Driver, make sure LogosXT is running and not the old Logos service.

  1. Save the file to C:\Users\{username}\AppData\Roaming\Helios\TextPad\{TextPadVersion}
  2. Open TEXTPAD, click on Configure > New Document Class
  3. Enter NUCARS as the new class name and select Next


NUCARS® is a dynamic and adaptable multi-body dynamics software. Learn from MxV Rail experts how to best utilize NUCARS® and its capabilities to address your needs.

Tailored training sessions include:

Pre-processors for:

  • Track Geometry
  • Wheel and Rail Profiles
  • Input forces
  • Eigenvalue analysis
  • System masses, stiffness, damping, friction etc.
  • Springs
  • Batch generation

Plotting and animation outputs

  • Plotting and animation outputs
    • 2D or 3D animation bodies
    • Animation of wheel/rail profile contact
    • Statistics and plots of data channels

Simulation of 1, 2, & 3 Degree of Freedom (DOF) Systems

  • Initial conditions
    • Input with input bodies
    • Input with forcing function
    • Review of simple rigid body car dynamics

4-Axle Freight or Passenger Vehicle example review of simple body car dynamics

  • Vehicle model
  • AAR chapter 11 track geometry inputs

Steady State Curving

  • Theory
  • Performance criteria (including derailment)
  • Hunting
  • Batch data analysis

Hunting/Lateral Stability

  • Integration time step checks

Multiple Wheel/Rail Profiles

  • Variation or rail profiles along track
  • Different wheel profiles on each axle

Measured track geometry input

Connection types in NUCARS®

Multi-Body Track Model


Double Rail Model

Flexible bodies


Talk with an expert about how NUCARS® software solution can address your needs

Get in touch