Highway And Railroad Engineering Simulations

A collection of interactive 3D visualizations and simulations to help you master concepts in highway and railroad engineering.

Geometric Design: Horizontal Alignment - Theory & Concepts

Principles of designing horizontal curves, calculating required superelevation rates, and ensuring adequate sight distances for safe vehicle operation.

Superelevation Calculator

Design Speed (V): 80 km/h

Curve Radius (R): 400 m

Results

Max Safe Friction ($f_{max}$):0.14

Required Superelevation ($e$):0.0%

Safe

F_c

Cross-section view (exaggerated forces)

Geometric Design: Vertical Alignment - Theory & Concepts

Design of crest and sag vertical curves, calculating elevations, and ensuring adequate sight distance over hills and under bridges.

Stopping Sight Distance (SSD) Simulator

Adjust the parameters to see how velocity, reaction time, road friction, and grade affect the total distance required for a vehicle to come to a complete stop.

Design Speed (V)60 km/h

Reaction Time (t)2.5 s

Coeff. of Friction (f)0.35

(Lower = wet/slippery, Higher = dry/rough)

Grade (G)0%

(- = Downgrade, + = Upgrade)

Reaction Dist.

41.7 m

Braking Dist.

40.5 m

Total SSD

82.1 m

Visual Representation

Perception-Reaction

Braking

250m Scale

Geometric Design: Cross-Section - Theory & Concepts

Design and function of highway cross-sectional elements including travel lanes, shoulders, medians, and right-of-way.

Highway Cross-Section Builder

Lanes per Direction:2

Lane Width:3.6 m

Shoulder Width:3 m

Divided Median5 m

Traffic Engineering Studies - Theory & Concepts

Core methodologies for collecting, analyzing, and applying traffic data to improve road networks, including volume, speed, and flow modeling.

Level of Service (LOS) Simulator

Current LOSB

Avg Speed68 mph

"Reasonably free flow. Freedom to maneuver is slightly restricted."

Traffic Density15 pc/mi/ln

Based on Highway Capacity Manual (HCM) density thresholds for basic freeway segments.

Traffic Control Devices - Theory & Concepts

Design, application, and legal requirements of traffic signs, pavement markings, and traffic signals to regulate, warn, and guide road users.

Traffic Signal Timing Simulator

Adjust the cycle length and phase distributions to observe how green, amber, and all-red clearance intervals allocate time to competing traffic streams at an intersection.

Cycle Length ($C$)60 sec

East-West Green Phase30 sec

Amber Phase3 sec

All-Red Clearance2 sec

Time: 0s / 60s

North/South

🛣️

East/West

E/W Green

N/S Green

Highway Materials - Theory & Concepts

Properties, classification, and testing of subgrade soils, aggregates, asphalt, and concrete used in pavement construction.

Aggregate Gradation Visualizer

Select a gradation type to see its characteristics.

Characteristics: Dense-Graded (Well-Graded): Contains a continuous distribution of aggregate sizes from coarse to fine. This results in minimal void space and high stability due to aggregate interlock.

Flexible Pavement Design - Theory & Concepts

Principles of flexible pavement structure, the AASHTO 1993 design method, Structural Number (SN), and layer thickness calculations.

AASHTO Flexible Pavement Design

Design Inputs

Traffic (ESALs):5 Million

Subgrade $M_R$:5,000 psi

Lower $M_R$ means weaker soil, requiring a thicker pavement.

Reliability ($R$):90%

Layer Thicknesses (inches)

Surface ($D_1$, $a_1=0.44$):4"

Base ($D_2$, $a_2=0.14$):6"

Subbase ($D_3$, $a_3=0.11$):8"

Required SN:0.00

Provided SN:0.00

✅ DESIGN ADEQUATE

30" -

20" -

10" -

0" -

HMA Surface (4")

Base Course (6")

Subbase (8")

Subgrade$M_R$ = 5000 psi

Rigid Pavement Design - Theory & Concepts

Structural design of Portland Cement Concrete (PCC) pavements, covering slab thickness, subbase support, and joint detailing.

Rigid Pavement Thickness Calculator

Traffic Loading (ESALs)15 Million

Higher traffic volume requires a thicker slab to prevent fatigue failure.

Concrete Flexural Strength (S'c)4.5 MPa

Stronger concrete can withstand higher tensile stresses without cracking.

Modulus of Subgrade Reaction (k-value)40 MPa/m

Stiffer subgrade/subbase provides better support, reducing required thickness.

Include Dowel Bars (Load Transfer)

Tied Concrete Shoulders

Required Slab Thickness

250 mm

250 mm PCC Slab

Subbase / Subgrade (k = 40 MPa/m)

Load Transfer Coefficient (J): 2.8

* Simplified calculation for educational purposes.

Highway Construction and Maintenance - Theory & Concepts

Earthwork operations, equipment selection, quality control during construction, and common pavement distresses and rehabilitation strategies.

Mass Haul Diagram Simulator

Visualize cumulative earthwork volumes along the alignment.

Loading chart...

Interpretation: A rising line indicates excess cut material available for hauling forward. A falling line indicates a need for fill material. When the curve crosses the red zero-line, cut and fill volumes are exactly balanced at that station.

Railroad Engineering Basics - Theory & Concepts

Fundamentals of the railway track structure, including rails, ties, ballast, subgrade, and the principles of track geometry.

Railway Track Structure

Controls

Track Gauge (mm): 1435

Narrow (1000)Standard (1435)Broad (1676)

Highlight Component:

Info

The track structure distributes immense point loads from the wheels safely to the subgrade.

←1435 mm Gauge→

Railroad Operations and Control - Theory & Concepts

Train resistance, required tractive effort, signaling systems, track capacity, and high-speed rail operations.

Train Resistance (Davis Equation)

Train Type:

Speed ($V$): 60 km/h

Track Grade: 0%

Even a 1% grade dramatically increases total resistance for heavy trains.

Total Resistance at 60 km/h

196 kN

Aero ($CV^2$)36

Flange ($BV$)60

Rolling ($A$)100

Loading chart...

Airport Engineering Fundamentals - Theory & Concepts

Principles of airport planning, wind rose analysis for runway orientation, and geometric design including runway length corrections.

Runway Length Correction Simulator

Basic Length:1800 m

Elevation:600 m MSL

Air density decreases at higher altitudes.

Reference Temp (ART):24°C

Std. Temp at 600m is 11.1°C.

Effective Gradient:0.6%

Sequential Corrections

1. Elevation Corrected:2052.0 m

2. Temp Corrected (Applied to #1):2316.7 m

3. Gradient Corrected (Applied to #2):2455.7 m

Final Required Length:2455.7 m

+36.4% penalty

BASIC

0m2455.7m