Plan heavy construction rail moves with force estimates. Model grade, curves, rolling drag, and inertia. Validate adhesion, compare scenarios, and share clean reports quickly.
Enter project values. Defaults are typical starting points and may not match your fleet.
| Case | Mass (t) | Speed (km/h) | Grade (%) | Radius (m) | Accel (m/s²) | μ | Adhesive (t) | Output TE (kN) |
|---|---|---|---|---|---|---|---|---|
| Baseline haul | 1200 | 40 | 1.0 | 0 | 0.10 | 0.25 | 300 | ≈ calculated |
| Steeper segment | 1200 | 30 | 2.0 | 0 | 0.05 | 0.28 | 320 | ≈ calculated |
| Curved alignment | 900 | 35 | 0.8 | 250 | 0.08 | 0.30 | 260 | ≈ calculated |
Tractive effort is the pulling force at the wheel–rail interface that must overcome all opposing forces. In construction rail logistics, a realistic budget helps confirm that a consist can start, accelerate, and hold speed on the ruling grade while meeting schedule windows. This calculator combines resistances into a single force so planners can compare scenarios and document assumptions.
Total mass sets the baseline resistance and grade load. Speed influences rolling resistance and required power, so small speed changes can shift energy demand and locomotive loading. Acceleration adds an inertial term using an equivalent mass that accounts for rotating components. Curve radius adds additional drag when alignment is not tangent.
The Davis equation models rolling resistance per tonne using constants A, B, and C, with speed in kilometres per hour. Default values provide a starting point, but project teams should tune constants with test runs, wagon type data, and maintenance condition. Curve resistance is represented with an adjustable coefficient K divided by radius, which can be refined for site geometry.
Available tractive effort is limited by adhesion between steel wheels and rail. The adhesion limit is estimated from adhesive weight on driven axles and a friction coefficient mu. If required effort exceeds this limit, the train may slip, especially in wet, dusty, or contaminated conditions. Mitigations include sanding, reducing acceleration, lowering speed, shortening the train, or adding locomotives.
Outputs include a force breakdown, total tractive effort, and power at the selected speed. These values support haul planning, energy estimates, and equipment selection, but they do not replace detailed route studies. Use conservative inputs, validate against known performance, and review braking needs for negative grades. Exported CSV and PDF files improve traceability for design reviews. For procurement, compare multiple locomotive consists and note margin to adhesion. Capture weather assumptions, wheel condition, and track cleanliness explicitly today.
It is the total wheel–rail force required to overcome resistance, grade, curves, and inertia at the chosen speed and acceleration.
Rolling resistance typically increases with speed, raising force. Power equals force times speed, so higher speed also increases kilowatt demand.
Use measured test data when possible. Otherwise start with defaults, then calibrate using known fuel, current draw, or performance on a reference segment.
Enter a negative grade. The grade term becomes negative, which can reduce required tractive effort and indicate braking effort may be needed.
It is required tractive effort divided by the adhesion limit. Values above 100% indicate likely wheel slip without operational changes or traction aids.
Use it for planning and comparisons. For final decisions, confirm route geometry, braking analysis, locomotive ratings, and site-specific resistance measurements.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.