2020 NUCARS® and TOES™/STARCO™ User Group Meeting Registration

Date: March 12, 2020

Time: 8 am to 5 pm

Location: DoubleTree by Hilton-Colorado Springs, CO

TTCI is very happy to again be hosting the user group meeting for TTCI's software products. Based on feedback from pervious years, we are going to try some new techniques for conducting this meeting.

First, we will be opening up the meeting to allow for electronic attendance and participation. This will be accomplished through a GoToMeeting portal. As the meeting approaches, we will contact registered attendees with details for attending and confirming their mode of attendance (electronic or in-person).

Second, we are looking for attendees willing to present case studies on their use of TTCI software. While employees at TTCI are heavy users of our own software, we are always interested how people outside our organization use the software. Additionally, it is our belief that this meeting should be user focused and can be user led. Your participation as a presenter would be greatly appreciated and we believe would improve the quality of this meeting.

Finally, we are asking for your questions and input about which areas interest you most. While we get the opportunity to answer questions as a group at the meeting, being able to prepare for questions gives us the opportunity to present examples as part of the explanation. During your registration, please provide any topics you might like to see covered in the meeting.

Questions regarding the User Group meeting – Please contact Devin Sammon (719-584-0702 or Devin_Sammon@aar.com )

Agenda coming soon




Are you willing to present a case study?

We offer NUCARS® training classes on request.

Training classes can be held at our site or yours.
Topics and example files can be tailored to fit your needs. (Units in English or metric)

Some of the topics that can be presented during a 5 day class:            

Computer Setup

Introduction to the NUCARS® Program and Subprograms

  • Pre-processors for:
    • Track Geometry
    • Wheel and Rail Profiles
    • Input forces
    • Eigenvalue analysis
    • System masses, stiffnesses, damping, friction, etc.
    • Springs
    • Batch generation
  • Post-Processors for:
    • Plotting and animating outputs
      • 2- or 3-d animation of 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

Wheel and Rail profiles

Wheel/Rail Contact Models          

  • Rigid contact
  • Online, multi-point contact
  • Back-of-flange contact (Guardrails, Switch Point protectors)

Multiple Wheel/Rail Profiles

  • Variation of Rail profiles along the track  
  • Different Wheel profiles on each axle

Measured track geometry input  

Connection types in NUCARS®

Multi-Body Track Model


Double Rail Model

Flexible bodies

NUCARS®: What you can do

• Research & Development

• Wheel & Rail profile optimization

• Derailment investigation

• Vehicle & Track design

• Prototype evaluation

• Customizable to suit your project and needs

NUCARS® : What You Get

NUCARS® Software

Multi-body dynamic simulation integration engine

  • NUCARS® Control Panel
Program for launching the individual programs

Prepares measured wheel and rail profile shapes for input to NUCARS, batch processing of multiple wheel and rail profiles available

  • TrackVu

Preview, analyze, and prepares measured track geometry for input to NUCARS.

  • SpringVu

Calculates input data for standard North American 3-piece truck freight car spring groups and friction wedges

  • MultiVu™

A very powerful data analysis package for the analysis and plotting of NUCARS® output, including time domain and frequency domain analyses, digital filtering, ride quality, statistics, and conversion to other data formats. Most functions are also available for batch processing. Output data channels can also be combined and manipulated using a variety of mathematical functions. MultiVu™ also accepts ASCII input from other data sources, such as test data.


Preprocessor for viewing NUCARS® system files and checking their validity


Animation of NUCARS® and NUEIGEN output, including visualization of W/R forces and body motions


Eigen-value solution for linearized systems including lateral stability (hunting)

  • Track Propagator

For generating the track portion of NUCARS SYS files to represent flexible track structures for use with the NUCARS flexible track modeling capability.

  • ParamVu

Allows easy generation of many NUCARS input data files (SYS, RUN, ETC) with varied inputs for parameter variation simulations.


  • PDF file for ease of searching and printing.


NUCARS® Input File Libraries (supplied with License)

  • Representative vehicles for standard freight car, 2-axle car, 4-axle locomotive
  • Theoretical AAR Chapter XI track inputs
  • Measured TTC Track geometry
  • Representative theoretical and measured wheel/rail profiles and contact geometry
  • Arema 20 turnout

    Full simulations of:
    • new wedge connections
    • track model with bending rail ("single layer" track model)
    • track model with bending rail and ties ("double layer")
    • a slid flat wheel
    • wheel/rail animation


Future NUCARS® Developments

TTCI continues to develop software for NUCARS to support TTCI’s ongoing research and development for the Association of American Railroads (AAR) and worldwide railroad industry customers. This was recently demonstrated in the release of a comprehensive multibody track model within NUCARS, and the computation of wheel/rail contact geometry in real time. Current development efforts are focused on the inclusion of more nonlinear suspension elements commonly used in the railway industry, and improving the user interface.  The following are a few of the major items that are currently in the works.

Ongoing development of the improved UI including:

  • Include the SYS file modification capabilities of SYSMOD
  • Include the capabilities of SPRINGVU spring data calculator
  • Include track model features and the capabilities of the Track propagator pre-processor program
  • Integration with MULTIVU for analysis and display of output results
  • Include the capabilities of the PARMVU parameter variation program


  • Conformal W/R contact
  • Ongoing development of double rail model for improved simulations of switch points, guard rails and other special trackwork
  • Ongoing improvements to the recent release
  • Individual wheel profile shapes for each axle
  • Improved simulation of variations in rail profile along the track
  • Ongoing improvements to the W/R contact animation
  • Online calculation of Kalker creep coefficients and contact parameters by link to CONTACT program.


  • Falling W/R Friction Coefficient
  • Allow continuous varying of W/R friction coefficient as a function of position on the wheel or rail surface
  • Improve the ability to change Kalker creep curve for each contact patch by allowing it to vary along the track


  • W/R contact model to take into account wheelset flexible modes


  • Ongoing university research partnership under AAR affiliated labs program22
  • True stick-slip for wedges
  • More complex wedges such as split wedge
  • Variable toe in/out across column wear surface


  • Improved simulation of air suspensions using built-in models, including:
    • simple and direct simulation of piping interconnections between individual suspensions
    • active simulation of leveling valves and differential pressure valves


  • Improve the capabilities of the NUCARS user interface to quickly simulate variations in any NUCARS input parameter
  • Improve the MultiVu post processor to accommodate large data bases of NUCARS simulations results from parameter variation studies
  • Improve the NUCARS input data preprocessing software


  • Continue development of experimental capability within NUCARS to predict worn wheel and rail shapes based on iterative running of NUCARS simulations[20].


NUCARS® Validation and Benchmarking

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 TTCI's customers worldwide in the passenger and freight railway industry.

There was an error, please click here to try again.

User Support Request Form

Security or License related?

Security or License Issue

Make sure you have the drivers installed. They can be found here.

Please describe your issue. Include screenshots of any errors you see.

If your key battery has died, please enter your shipping address below and a replacement key
will be sent along with a pre-paid return shipping label for your old key.

Shipping Address

If your license has expired, please attach a update request file.
For instructions on generating this file, click here.

Sub program:

Bug Report

Program Version:

(Example: TrackVu 2014.2.1, you can find this information in the about box.)

Description of unexpected behavior:

Attach simulation files necessary to recreate the issue.
(Your file will be used only to support your issue and must be a .zip)

Feature Request

Description of new behavior:

Anti spam captcha:

Quick Tips

TextPad® Text Editor From The NUCARS® Team

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. TTCI 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.

To find out more about TextPad® and to download TextPad® 4.7.3 click the logo below.
After you download and install TextPad® you can download a beta version of a NUCARS® syntax sheet.
Then to activate the syntax highlighting:
  1. Save the file to C:\Program Files\TextPad 4\Samples
  2. Open TextPad, click on Configure->New Document Class...
  3. Enter "NUCARS" as the new class name and select NEXT
  1. Enter all the files you want to be included in the new class
    • *.run, *.sys, *.dat, *.inp, *.wnt, *.wrm, *.frc, *.lst, etc
  1. Select NEXT

  2. Select "Enable syntax highlighting" check box and select NUCARS.syn from the syntax defenition file drop-down menu
  1. Select NEXT then FINISH


Slow or Non-Responsive Closure of NUCARS® Programs in Windows XP From Wil Lundberg

When a program hangs up and is not responsive, on earlier versions of Windows (2000, 98, NT, 95, etc) you could either Ctrl-Alt-Del and kill the program from the task manager or you could click on the X button at the top-right. You can still do this in XP, but with some programs, typically ones with high amounts of memory utilization (i.e. NUCARS, MultiVu, AutoCAD, etc) the killing process will take almost 100% of processor capability and can take several minutes. Typically after the process is killed, the computer as a whole tends to operate at a lesser degree of performance. The only way in the past that I found to fix this problem was to restart my computer. What is using all of the processor load is a program Microsoft has loaded onto your computer to generate error reports of programs that you have ended with Ctrl-Alt-Delete, Alt-F4 or the X button. Without getting into too much detail, memory maps and other diagnostic information are being prepared so that the user can send it to Microsoft so that they can fix the problem / send it to the vendor / etc.

To prevent all this from happening and to return the computer system to it's full capabilities, you can run the following from the command line from Start->Run

  • TASKKILL /F /IM (Executable Name)
So to kill NUCARS_2004A.exe, you would type in:
  • TASKKILL /F /IM NUCARS_2004A.exe.
Or you can use a filter if you don't know the whole name, such as:
and that will kill all processes which start with NUCARS.

If you have any questions on the above method, please do not hesitate to contact the NUCARS® help desk.



  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"


NUCARS®: Recent Updates and Revisions

NUCARS® Software

  • Improved Algorithms for Simulation of Link Type Suspension
    • New algorithms for all connection types except wheel/rail connections
    • Increases accuracy of calculation of angular motions
    • Involved improving the small angle calculation approximations to:
      • sinφ = φ
      • cosφ = 1 - φ² / 2
    • Previous small angle assumptions were: (as described section 1.5 of Users Manual.)
      • sinφ = φ
      • cosφ = 1
    • Has resulted in increased accuracy for simulation of suspension elements such as radial arms, swing hangers and other link type suspensions, including the roll motions
      of sideframes in 3-piece trucks such as the Swing Motion™ truck.
  • NUCARS Batch File creation tool in NUCARS®
  • Wheel/Rail Penetration Contact Model
    • Increases realism and accuracy of wheel/rail force calculations by use of multiple overlapping contact patches and a penetration algorithm
    • Reduces unstable wheel/rail force contact calculations
    • Realistic representation of conditions leading to rolling contact fatigue (RCF) and wear
    • Includes capability to vary rail profile shapes along the track
  • Animated Output of the Wheel/Rail Contact Geometry from the Penetration Model using MultiVu™
  • Beta Version of a Multibody - Track model within NUCARS®
  • Beta Version of a New TrakVu™ Track Geometry Pre-Processor Program.
    • Features an improved user interface and increased analysis capabilities based on the MultiVu™ data analysis post-processing program
  • New Connection Types
    • Type 6.8 (friction wedge model with stick-slip friction)
    • Type 6.9 (stick-slip friction wedge model with longitudinal force transmission and concave column wear surface (variable toe-in/toe-out)
  • NUCARS: Revised and improved "equilibrium" calculations
  • MULTIVU: More mathematical functions, improved graphics and output, increased batch processing capabilities.
  • Revised and updated library of wheel/rail profiles and contact geometry files
  • Updates and revisions available by download from the here.

NUCARS® Capabilities and Features

  • Multi-body simulation tool simulates any rail vehicle on any track
    • Locomotives
    • Passenger vehicles
    • Freight vehicles
    • Articulated cars
    • Multiple cars coupled together
  • Track geometry inputs may be theoretical or actual track measurements
    • Curvature and superelevation
    • Turnout geometry
    • Track crosslevel, alignment, gauge, and profile deviations
    • External forces
  • Wheel/rail force calculation
    • Forces calculated using Kalker's non-linear creep theory, [8]
    • Measured and theoretical wheel and rail profile shapes
    • Wheel profile shapes may be specified individually for each wheel
    • Two point wheel/rail contact
    • Rail profile shapes may vary along the track
    • Coefficient of friction may vary along track and across rail/wheel surface
    • Flange back contact for guard rails, turnouts and special trackwork, [5,7,9]
    • Optional traction and braking forces
    • Optional torsionally flexible axles
    • Optional independent rotating wheels
    • Optional torsional links between axles
    • Optional drive gears on axles
  • Vehicle bodies may be flexible with up to 89 modes in each principal direction
  • Suspensions described as combinations of connection elements - on or off the principal X-Y-Z axes
    • Parallel and series springs and dampers
    • Hysteresis elements
    • Stops and gap elements
    • Friction line and surface elements, including stick/slip
    • Friction wedges with optional toe in/out (for 3-piece freight trucks)
    • Air springs can be easily simulated as combinations of standard connection elements
    • Active suspensions (such as tilting trains)
  • NUCARS® Outputs
    • All body motions, velocities and accelerations
    • Eigen-values and Eigen-vectors (from NUEIGEN)
    • Wheel/rail forces in X, Y, Z and contact patch coordinates
    • Wheel/rail contact point geometry, creepages, creep forces, and contact stresses
    • Suspension forces and motions
    • Wheel and rail wear indices on flange/gauge face and tread/railhead
    • Simulated transducers

Latest News

July 31, 2019
The 2019.2 NUCARS® update is now available on the Downloads Page for licensed users.

January 30, 2019
The 2019.1 NUCARS® update is now available on the Downloads Page for licensed users.

November 19, 2018
The signup for the 2019 NUCARS® and TOES™/STARCO™ User Group Meeting is now available here.

January 3, 2018
We will be offering a NUCARS® training course the week of May 14th in Chicago, Illinois.
For more information and to sign-up, please contact Carmen Trevizo (719-584-0560) or MaryClara Jones (719-585-1808). 

Check here for instructions on how to update your NUCARS® key.

Key Instructions

All NUCARS® keys will expire on January 31, 2019. Please read the following instructions carefully so that we can reset your key for 2019.

Step 1: Send Update Request

Go to Step 2 if you have already sent your request and received your update file.
  • Launch the NUCARS® 2019 - 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 (The key # is the 5 digit number engraved on the back of the key below TTCI-NUCARS)
  • Email the file to: nucars@ttci.aar.com 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 for 2019 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.

Step 2: Updating your Key

If you sent a request to update your key and we have received payment you will be receiving an update file to be used to extend your license to January 31, 2019. If you have multiple keys, make sure the correct update file is used, as this file is unique to request file that was sent for each key.

To perform the license update:

  • Select Tools -> Request License Update on the 2019 NUCARS Control Panel to launch the SafeNet Secure Update Utility
  • In the dialog box, click on the folder to find the .upw file you received by email
  • Click the Activate Application button.
  • Exit

If the update has been performed successfully, the control panel will now show a license expiration date of January 31st, 2019.

Supporting Files

SafeNet Sentinel Key Driver

Many technical problems invovling 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)

Sentinel Protection Installer v7.6.9 - Download Here

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. To disable-

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
Place the following text in that file:


TextPad® Syntax Sheet

Download a beta version of a NUCARS® syntax sheet for TextPad®.



Download NUCARS® 2019.2 - July 31, 2019

See the Release notes within the user manual for more information.

Installation Instructions:
  • You must have the key drivers installed previous to installing. Download Here
  • Connect your NUCARS hardware key to your computer.
  • Download and run the installation program.
  • The program will determine if your license is valid.
  • If the license is valid, the install program will then install the full NUCARS Installation.
  • If the license is not valid, see below about updating your key.

Download Issues

If you experience issues downloading the install in Internet Explorer web browser, please use Chrome or Firefox web browsers to download the files. Alternatively, if you use Internet Explorer web browser, you can download by selecting "View Downloads", right-clicking on the IntegratedModelingSetup.msi, and select "Run anyway."


Updating Your Key
We do not send out new keys for renewing customers. If you've renewed your license for 2018,
click here for instructions on how to update your key.

Click here to request a CD
(Licensed Users Only)

If you have any questions regarding installation of these upgrades, security keys or use of NUCARS®, please contact the NUCARS Help Desk at (800) 265-3184, Monday - Friday, 7 a.m. to 4:30 p.m. MST, or use the User Support Request Form.


TTCI's well-known railway multi-body dynamics computer program, NUCARS®, simulates the dynamic response of a railroad vehicle to specified track conditions. NUCARS® is capable of predicting the rsponse of any rail vehicle; locomotive, passenger, transit, or freight car on any type of track geometry, including special track work such as turnouts and guardrails. The program is ideal for evaluating and comparing new vehicle designs as well as performing failure analyses such as derailment studies. NUCARS® is also used to investigate and improve ride quality.

NUCARS® is a general multi-body rail vehicle dynamics computer simulation model. It is designed to simulate the dynamic interaction of any rail vehicle with virtually any track. The user may select any number of bodies, degrees of freedom, and connection elements to describe a vehicle and track system. NUCARS® can be used to analyze the dynamic interaction of rail vehicles and track to predict stability, ride quality, vertical and lateral dynamics, and steady state and dynamic curving response. The program includes detailed nonlinear models of wheel/rail interaction and suspension response, with wheel/rail interaction based on Kalker's complete non-linear creep theory. Applications are in the areas of vehicle design, safety performance evaluation, rail vehicle and track research, derailment investigation, and general simulation of mechanical systems. Simulations of any type of freight, passenger, transit and locomotive rail vehicles are possible. Track simulations may include hypothetical track geometries or measured track supplied by the user, including turnouts and guard rails.


Typical NUCARS® Applications

  • Vehicle Design Optimization.
    Changes to suspension characteristics and vehicle geometry can be quickly simulated and the effects on ride quality, vehicle curving and safety performance are easily determined. A wide range of suspension elements can be included in a NUCARS® model including a number of detailed friction models designed to simulate specific railroad vehicle suspension components, as well as normal spring and damping components. Advanced vehicle designs that include items such as articulation, self steering axles, independently rotating wheels, air bag suspensions and viscous dampers are just a few of the possibilities. Special connection elements are included to represent tilting and active suspensions.
  • Derailment Investigation.
    Derailment conditions can be simulated with the input of measured track geometry data, actual wheel and rail profile shapes. The specifications of actual vehicle suspension conditions and the presence of unusual conditions and external forces acting on the car can be input to the NUCARS® model to permit the user to explore the wheel/rail interaction forces and other dynamic conditions that lead to derailment.
  • Track Component Design.
    NUCARS® can be used to explore changes in track design such as turnout geometry and guard rail configuration. The wheel/rail interaction forces can be calculated and track designs optimized to minimize their effects on the track structure.
  • Vehicle Certification.
    NUCARS® is an especially useful tool in evaluating vehicle safety performance. NUCARS® can significantly enhance the certification tests such as the AAR Chapter XI tests for new freight cars by permitting prediction actual tests as well as conditions not possible to test. NUCARS® simulations can be conducted up to the point of derailment to establish overall windows of performance.
  • Wheel and Rail Profile Design Optimization.
    NUCARS® wheel/rail interaction calculations permit the user to explore the effects of profile shapes on wheel/rail forces, wheel/rail wear, and vehicle dynamic performance. The trade off between high conicity wheel profiles for good curving performance and low conicity profiles for high-speed stability can be quickly quantified. Output of various wheel/rail contact parameters such as creep forces, contact angles and wheel rolling radii allow a detailed study of the wheel/rail interaction.
  • Vehicle Ride Quality.
    Passenger comfort evaluations and lading damage studies can be performed with NUCARS® by simulation of vehicles running over measured track data. Output variables allow the simulation of actual transducers such as accelerometers mounted anywhere on the car structure to simulate actual test instrumentation.
  • Wheel/Rail Lubrication Studies.
    By varying the coefficient of friction in the tread, flange and flange back regions analyses can be made of the effects of lubrication on wheel and rail wear, rolling resistance and vehicle curving performance.
  • Rolling Contact Fatigue (RCF) Studies.
    Small variations of wheel and rail profile shapes, wheel/rail lubrication, in combination with vehicle curving dynamics have been shown to have significant impact on RCF. NUCARS® has the ability to evaluate all these parameters singly or in combination, allowing detailed studies of the RCF mechanisms.
  • Dynamic Clearance Envelope Calculations.
    Clearances between moving vehicles on adjacent tracks, and between vehicles and stationary objects such as bridges, poles and platforms can be calculated from NUCARS® from NUCARS® simulations of vehicles running over track curves, super elevation and track perturbations.


NUCARS® has been available under license from TTCI since the late 1980's. Current licensees of the NUCARS® program include North American Railroads, North American car builders, locomotive builders, and component manufacturers, as well as overseas railways, car builders and track suppliers.


Licensing Inquiries

Tel: +1-888-588-7246

Email: marketing@aar.com

NUCARS Help Desk

Tel: +1-800-265-3184

Email: nucars@ttci.aar.com


Transportation Technology Center, Inc.
55500 DOT Road
Pueblo, Colorado 81001

Tel: +1-719-584-0750
Fax: +1-719-584-0711
TTCI on the Web



This is bold and this is strong. This is italic and this is emphasized. This is superscript text and this is subscript text. This is underlined and this is code: for (;;) { ... }. Finally, this is a link.

Heading Level 2

Heading Level 3

Heading Level 4

Heading Level 5
Heading Level 6


Fringilla nisl. Donec accumsan interdum nisi, quis tincidunt felis sagittis eget tempus euismod. Vestibulum ante ipsum primis in faucibus vestibulum. Blandit adipiscing eu felis iaculis volutpat ac adipiscing accumsan faucibus. Vestibulum ante ipsum primis in faucibus lorem ipsum dolor sit amet nullam adipiscing eu felis.


i = 0;

while (!deck.isInOrder()) {
    print 'Iteration ' + i;

print 'It took ' + i + ' iterations to sort the deck.';



  • Dolor pulvinar etiam.
  • Sagittis adipiscing.
  • Felis enim feugiat.


  • Dolor pulvinar etiam.
  • Sagittis adipiscing.
  • Felis enim feugiat.


  1. Dolor pulvinar etiam.
  2. Etiam vel felis viverra.
  3. Felis enim feugiat.
  4. Dolor pulvinar etiam.
  5. Etiam vel felis lorem.
  6. Felis enim et feugiat.





Name Description Price
Item One Ante turpis integer aliquet porttitor. 29.99
Item Two Vis ac commodo adipiscing arcu aliquet. 19.99
Item Three Morbi faucibus arcu accumsan lorem. 29.99
Item Four Vitae integer tempus condimentum. 19.99
Item Five Ante turpis integer aliquet porttitor. 29.99


Name Description Price
Item One Ante turpis integer aliquet porttitor. 29.99
Item Two Vis ac commodo adipiscing arcu aliquet. 19.99
Item Three Morbi faucibus arcu accumsan lorem. 29.99
Item Four Vitae integer tempus condimentum. 19.99
Item Five Ante turpis integer aliquet porttitor. 29.99


  • Disabled
  • Disabled